diff --git a/README.md b/README.md
index 639b0d9925e..5f828e75a23 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,7 @@ If you are using Maven without the BOM, add this to your dependencies:
 If you are using Gradle 5.x or later, add this to your dependencies:
 
 ```Groovy
-implementation platform('com.google.cloud:libraries-bom:26.54.0')
+implementation platform('com.google.cloud:libraries-bom:26.55.0')
 
 implementation 'com.google.cloud:google-cloud-spanner'
 ```
diff --git a/generation_config.yaml b/generation_config.yaml
index 257ca065090..a6a7866d7e2 100644
--- a/generation_config.yaml
+++ b/generation_config.yaml
@@ -1,6 +1,6 @@
 gapic_generator_version: 2.53.0
-googleapis_commitish: 9605bff3d36fbdb1227b26bce68258c5f00815e4
-libraries_bom_version: 26.54.0
+googleapis_commitish: 6bc8e91bf92cc985da5ed0c227b48f12315cb695
+libraries_bom_version: 26.55.0
 libraries:
   - api_shortname: spanner
     name_pretty: Cloud Spanner
diff --git a/google-cloud-spanner-executor/src/main/resources/META-INF/native-image/com.google.cloud.spanner.executor.v1/reflect-config.json b/google-cloud-spanner-executor/src/main/resources/META-INF/native-image/com.google.cloud.spanner.executor.v1/reflect-config.json
index 1b9c4de2d83..357035df837 100644
--- a/google-cloud-spanner-executor/src/main/resources/META-INF/native-image/com.google.cloud.spanner.executor.v1/reflect-config.json
+++ b/google-cloud-spanner-executor/src/main/resources/META-INF/native-image/com.google.cloud.spanner.executor.v1/reflect-config.json
@@ -1781,6 +1781,24 @@
     "allDeclaredClasses": true,
     "allPublicClasses": true
   },
+  {
+    "name": "com.google.spanner.admin.database.v1.BackupInstancePartition",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
+  {
+    "name": "com.google.spanner.admin.database.v1.BackupInstancePartition$Builder",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
   {
     "name": "com.google.spanner.admin.database.v1.BackupSchedule",
     "queryAllDeclaredConstructors": true,
@@ -6110,6 +6128,15 @@
     "allDeclaredClasses": true,
     "allPublicClasses": true
   },
+  {
+    "name": "com.google.spanner.v1.TransactionOptions$IsolationLevel",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
   {
     "name": "com.google.spanner.v1.TransactionOptions$PartitionedDml",
     "queryAllDeclaredConstructors": true,
diff --git a/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.admin.database.v1/reflect-config.json b/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.admin.database.v1/reflect-config.json
index 3b456d976d0..0d1524fb146 100644
--- a/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.admin.database.v1/reflect-config.json
+++ b/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.admin.database.v1/reflect-config.json
@@ -1781,6 +1781,24 @@
     "allDeclaredClasses": true,
     "allPublicClasses": true
   },
+  {
+    "name": "com.google.spanner.admin.database.v1.BackupInstancePartition",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
+  {
+    "name": "com.google.spanner.admin.database.v1.BackupInstancePartition$Builder",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
   {
     "name": "com.google.spanner.admin.database.v1.BackupSchedule",
     "queryAllDeclaredConstructors": true,
diff --git a/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json b/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json
index bcbb239a5be..20a93919949 100644
--- a/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json
+++ b/google-cloud-spanner/src/main/resources/META-INF/native-image/com.google.cloud.spanner.v1/reflect-config.json
@@ -2249,6 +2249,15 @@
     "allDeclaredClasses": true,
     "allPublicClasses": true
   },
+  {
+    "name": "com.google.spanner.v1.TransactionOptions$IsolationLevel",
+    "queryAllDeclaredConstructors": true,
+    "queryAllPublicConstructors": true,
+    "queryAllDeclaredMethods": true,
+    "allPublicMethods": true,
+    "allDeclaredClasses": true,
+    "allPublicClasses": true
+  },
   {
     "name": "com.google.spanner.v1.TransactionOptions$PartitionedDml",
     "queryAllDeclaredConstructors": true,
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientHttpJsonTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientHttpJsonTest.java
index 5d476f914a8..26826b4dd8d 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientHttpJsonTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientHttpJsonTest.java
@@ -48,6 +48,7 @@
 import com.google.protobuf.Timestamp;
 import com.google.spanner.admin.database.v1.AddSplitPointsResponse;
 import com.google.spanner.admin.database.v1.Backup;
+import com.google.spanner.admin.database.v1.BackupInstancePartition;
 import com.google.spanner.admin.database.v1.BackupName;
 import com.google.spanner.admin.database.v1.BackupSchedule;
 import com.google.spanner.admin.database.v1.BackupScheduleName;
@@ -1099,6 +1100,7 @@ public void createBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1168,6 +1170,7 @@ public void createBackupTest2() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1237,6 +1240,7 @@ public void copyBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1309,6 +1313,7 @@ public void copyBackupTest2() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1381,6 +1386,7 @@ public void copyBackupTest3() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1453,6 +1459,7 @@ public void copyBackupTest4() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1525,6 +1532,7 @@ public void getBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -1585,6 +1593,7 @@ public void getBackupTest2() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -1645,6 +1654,7 @@ public void updateBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     mockService.addResponse(expectedResponse);
 
@@ -1667,6 +1677,7 @@ public void updateBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     FieldMask updateMask = FieldMask.newBuilder().build();
 
@@ -1715,6 +1726,7 @@ public void updateBackupExceptionTest() throws Exception {
               .addAllBackupSchedules(new ArrayList<String>())
               .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
               .setOldestVersionTime(Timestamp.newBuilder().build())
+              .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
               .build();
       FieldMask updateMask = FieldMask.newBuilder().build();
       client.updateBackup(backup, updateMask);
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientTest.java
index 2424ad7bc27..fbc20ebbd9b 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/admin/database/v1/DatabaseAdminClientTest.java
@@ -51,6 +51,7 @@
 import com.google.spanner.admin.database.v1.AddSplitPointsRequest;
 import com.google.spanner.admin.database.v1.AddSplitPointsResponse;
 import com.google.spanner.admin.database.v1.Backup;
+import com.google.spanner.admin.database.v1.BackupInstancePartition;
 import com.google.spanner.admin.database.v1.BackupName;
 import com.google.spanner.admin.database.v1.BackupSchedule;
 import com.google.spanner.admin.database.v1.BackupScheduleName;
@@ -1013,6 +1014,7 @@ public void createBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1081,6 +1083,7 @@ public void createBackupTest2() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1149,6 +1152,7 @@ public void copyBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1221,6 +1225,7 @@ public void copyBackupTest2() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1293,6 +1298,7 @@ public void copyBackupTest3() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1365,6 +1371,7 @@ public void copyBackupTest4() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     Operation resultOperation =
         Operation.newBuilder()
@@ -1437,6 +1444,7 @@ public void getBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     mockDatabaseAdmin.addResponse(expectedResponse);
 
@@ -1491,6 +1499,7 @@ public void getBackupTest2() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     mockDatabaseAdmin.addResponse(expectedResponse);
 
@@ -1545,6 +1554,7 @@ public void updateBackupTest() throws Exception {
             .addAllBackupSchedules(new ArrayList<String>())
             .setIncrementalBackupChainId("incrementalBackupChainId1926005216")
             .setOldestVersionTime(Timestamp.newBuilder().build())
+            .addAllInstancePartitions(new ArrayList<BackupInstancePartition>())
             .build();
     mockDatabaseAdmin.addResponse(expectedResponse);
 
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/Backup.java b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/Backup.java
index 8b0895ebf50..9171639689c 100644
--- a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/Backup.java
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/Backup.java
@@ -48,6 +48,7 @@ private Backup() {
     referencingBackups_ = com.google.protobuf.LazyStringArrayList.emptyList();
     backupSchedules_ = com.google.protobuf.LazyStringArrayList.emptyList();
     incrementalBackupChainId_ = "";
+    instancePartitions_ = java.util.Collections.emptyList();
   }
 
   @java.lang.Override
@@ -1355,6 +1356,107 @@ public com.google.protobuf.TimestampOrBuilder getOldestVersionTimeOrBuilder() {
         : oldestVersionTime_;
   }
 
+  public static final int INSTANCE_PARTITIONS_FIELD_NUMBER = 19;
+
+  @SuppressWarnings("serial")
+  private java.util.List<com.google.spanner.admin.database.v1.BackupInstancePartition>
+      instancePartitions_;
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  @java.lang.Override
+  public java.util.List<com.google.spanner.admin.database.v1.BackupInstancePartition>
+      getInstancePartitionsList() {
+    return instancePartitions_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  @java.lang.Override
+  public java.util.List<
+          ? extends com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder>
+      getInstancePartitionsOrBuilderList() {
+    return instancePartitions_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  @java.lang.Override
+  public int getInstancePartitionsCount() {
+    return instancePartitions_.size();
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.admin.database.v1.BackupInstancePartition getInstancePartitions(
+      int index) {
+    return instancePartitions_.get(index);
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  @java.lang.Override
+  public com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder
+      getInstancePartitionsOrBuilder(int index) {
+    return instancePartitions_.get(index);
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -1426,6 +1528,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (((bitField0_ & 0x00000020) != 0)) {
       output.writeMessage(18, getOldestVersionTime());
     }
+    for (int i = 0; i < instancePartitions_.size(); i++) {
+      output.writeMessage(19, instancePartitions_.get(i));
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -1509,6 +1614,10 @@ public int getSerializedSize() {
     if (((bitField0_ & 0x00000020) != 0)) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(18, getOldestVersionTime());
     }
+    for (int i = 0; i < instancePartitions_.size(); i++) {
+      size +=
+          com.google.protobuf.CodedOutputStream.computeMessageSize(19, instancePartitions_.get(i));
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -1561,6 +1670,7 @@ public boolean equals(final java.lang.Object obj) {
     if (hasOldestVersionTime()) {
       if (!getOldestVersionTime().equals(other.getOldestVersionTime())) return false;
     }
+    if (!getInstancePartitionsList().equals(other.getInstancePartitionsList())) return false;
     if (!getUnknownFields().equals(other.getUnknownFields())) return false;
     return true;
   }
@@ -1628,6 +1738,10 @@ public int hashCode() {
       hash = (37 * hash) + OLDEST_VERSION_TIME_FIELD_NUMBER;
       hash = (53 * hash) + getOldestVersionTime().hashCode();
     }
+    if (getInstancePartitionsCount() > 0) {
+      hash = (37 * hash) + INSTANCE_PARTITIONS_FIELD_NUMBER;
+      hash = (53 * hash) + getInstancePartitionsList().hashCode();
+    }
     hash = (29 * hash) + getUnknownFields().hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -1775,6 +1889,7 @@ private void maybeForceBuilderInitialization() {
         getEncryptionInformationFieldBuilder();
         getMaxExpireTimeFieldBuilder();
         getOldestVersionTimeFieldBuilder();
+        getInstancePartitionsFieldBuilder();
       }
     }
 
@@ -1830,6 +1945,13 @@ public Builder clear() {
         oldestVersionTimeBuilder_.dispose();
         oldestVersionTimeBuilder_ = null;
       }
+      if (instancePartitionsBuilder_ == null) {
+        instancePartitions_ = java.util.Collections.emptyList();
+      } else {
+        instancePartitions_ = null;
+        instancePartitionsBuilder_.clear();
+      }
+      bitField0_ = (bitField0_ & ~0x00040000);
       return this;
     }
 
@@ -1875,6 +1997,15 @@ private void buildPartialRepeatedFields(com.google.spanner.admin.database.v1.Bac
       } else {
         result.encryptionInformation_ = encryptionInformationBuilder_.build();
       }
+      if (instancePartitionsBuilder_ == null) {
+        if (((bitField0_ & 0x00040000) != 0)) {
+          instancePartitions_ = java.util.Collections.unmodifiableList(instancePartitions_);
+          bitField0_ = (bitField0_ & ~0x00040000);
+        }
+        result.instancePartitions_ = instancePartitions_;
+      } else {
+        result.instancePartitions_ = instancePartitionsBuilder_.build();
+      }
     }
 
     private void buildPartial0(com.google.spanner.admin.database.v1.Backup result) {
@@ -2099,6 +2230,33 @@ public Builder mergeFrom(com.google.spanner.admin.database.v1.Backup other) {
       if (other.hasOldestVersionTime()) {
         mergeOldestVersionTime(other.getOldestVersionTime());
       }
+      if (instancePartitionsBuilder_ == null) {
+        if (!other.instancePartitions_.isEmpty()) {
+          if (instancePartitions_.isEmpty()) {
+            instancePartitions_ = other.instancePartitions_;
+            bitField0_ = (bitField0_ & ~0x00040000);
+          } else {
+            ensureInstancePartitionsIsMutable();
+            instancePartitions_.addAll(other.instancePartitions_);
+          }
+          onChanged();
+        }
+      } else {
+        if (!other.instancePartitions_.isEmpty()) {
+          if (instancePartitionsBuilder_.isEmpty()) {
+            instancePartitionsBuilder_.dispose();
+            instancePartitionsBuilder_ = null;
+            instancePartitions_ = other.instancePartitions_;
+            bitField0_ = (bitField0_ & ~0x00040000);
+            instancePartitionsBuilder_ =
+                com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders
+                    ? getInstancePartitionsFieldBuilder()
+                    : null;
+          } else {
+            instancePartitionsBuilder_.addAllMessages(other.instancePartitions_);
+          }
+        }
+      }
       this.mergeUnknownFields(other.getUnknownFields());
       onChanged();
       return this;
@@ -2245,6 +2403,20 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00020000;
                 break;
               } // case 146
+            case 154:
+              {
+                com.google.spanner.admin.database.v1.BackupInstancePartition m =
+                    input.readMessage(
+                        com.google.spanner.admin.database.v1.BackupInstancePartition.parser(),
+                        extensionRegistry);
+                if (instancePartitionsBuilder_ == null) {
+                  ensureInstancePartitionsIsMutable();
+                  instancePartitions_.add(m);
+                } else {
+                  instancePartitionsBuilder_.addMessage(m);
+                }
+                break;
+              } // case 154
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -5721,6 +5893,467 @@ public com.google.protobuf.TimestampOrBuilder getOldestVersionTimeOrBuilder() {
       return oldestVersionTimeBuilder_;
     }
 
+    private java.util.List<com.google.spanner.admin.database.v1.BackupInstancePartition>
+        instancePartitions_ = java.util.Collections.emptyList();
+
+    private void ensureInstancePartitionsIsMutable() {
+      if (!((bitField0_ & 0x00040000) != 0)) {
+        instancePartitions_ =
+            new java.util.ArrayList<com.google.spanner.admin.database.v1.BackupInstancePartition>(
+                instancePartitions_);
+        bitField0_ |= 0x00040000;
+      }
+    }
+
+    private com.google.protobuf.RepeatedFieldBuilderV3<
+            com.google.spanner.admin.database.v1.BackupInstancePartition,
+            com.google.spanner.admin.database.v1.BackupInstancePartition.Builder,
+            com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder>
+        instancePartitionsBuilder_;
+
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public java.util.List<com.google.spanner.admin.database.v1.BackupInstancePartition>
+        getInstancePartitionsList() {
+      if (instancePartitionsBuilder_ == null) {
+        return java.util.Collections.unmodifiableList(instancePartitions_);
+      } else {
+        return instancePartitionsBuilder_.getMessageList();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public int getInstancePartitionsCount() {
+      if (instancePartitionsBuilder_ == null) {
+        return instancePartitions_.size();
+      } else {
+        return instancePartitionsBuilder_.getCount();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public com.google.spanner.admin.database.v1.BackupInstancePartition getInstancePartitions(
+        int index) {
+      if (instancePartitionsBuilder_ == null) {
+        return instancePartitions_.get(index);
+      } else {
+        return instancePartitionsBuilder_.getMessage(index);
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder setInstancePartitions(
+        int index, com.google.spanner.admin.database.v1.BackupInstancePartition value) {
+      if (instancePartitionsBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.set(index, value);
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.setMessage(index, value);
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder setInstancePartitions(
+        int index,
+        com.google.spanner.admin.database.v1.BackupInstancePartition.Builder builderForValue) {
+      if (instancePartitionsBuilder_ == null) {
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.set(index, builderForValue.build());
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.setMessage(index, builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder addInstancePartitions(
+        com.google.spanner.admin.database.v1.BackupInstancePartition value) {
+      if (instancePartitionsBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.add(value);
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.addMessage(value);
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder addInstancePartitions(
+        int index, com.google.spanner.admin.database.v1.BackupInstancePartition value) {
+      if (instancePartitionsBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.add(index, value);
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.addMessage(index, value);
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder addInstancePartitions(
+        com.google.spanner.admin.database.v1.BackupInstancePartition.Builder builderForValue) {
+      if (instancePartitionsBuilder_ == null) {
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.add(builderForValue.build());
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.addMessage(builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder addInstancePartitions(
+        int index,
+        com.google.spanner.admin.database.v1.BackupInstancePartition.Builder builderForValue) {
+      if (instancePartitionsBuilder_ == null) {
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.add(index, builderForValue.build());
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.addMessage(index, builderForValue.build());
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder addAllInstancePartitions(
+        java.lang.Iterable<? extends com.google.spanner.admin.database.v1.BackupInstancePartition>
+            values) {
+      if (instancePartitionsBuilder_ == null) {
+        ensureInstancePartitionsIsMutable();
+        com.google.protobuf.AbstractMessageLite.Builder.addAll(values, instancePartitions_);
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.addAllMessages(values);
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder clearInstancePartitions() {
+      if (instancePartitionsBuilder_ == null) {
+        instancePartitions_ = java.util.Collections.emptyList();
+        bitField0_ = (bitField0_ & ~0x00040000);
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.clear();
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public Builder removeInstancePartitions(int index) {
+      if (instancePartitionsBuilder_ == null) {
+        ensureInstancePartitionsIsMutable();
+        instancePartitions_.remove(index);
+        onChanged();
+      } else {
+        instancePartitionsBuilder_.remove(index);
+      }
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public com.google.spanner.admin.database.v1.BackupInstancePartition.Builder
+        getInstancePartitionsBuilder(int index) {
+      return getInstancePartitionsFieldBuilder().getBuilder(index);
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder
+        getInstancePartitionsOrBuilder(int index) {
+      if (instancePartitionsBuilder_ == null) {
+        return instancePartitions_.get(index);
+      } else {
+        return instancePartitionsBuilder_.getMessageOrBuilder(index);
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public java.util.List<
+            ? extends com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder>
+        getInstancePartitionsOrBuilderList() {
+      if (instancePartitionsBuilder_ != null) {
+        return instancePartitionsBuilder_.getMessageOrBuilderList();
+      } else {
+        return java.util.Collections.unmodifiableList(instancePartitions_);
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public com.google.spanner.admin.database.v1.BackupInstancePartition.Builder
+        addInstancePartitionsBuilder() {
+      return getInstancePartitionsFieldBuilder()
+          .addBuilder(
+              com.google.spanner.admin.database.v1.BackupInstancePartition.getDefaultInstance());
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public com.google.spanner.admin.database.v1.BackupInstancePartition.Builder
+        addInstancePartitionsBuilder(int index) {
+      return getInstancePartitionsFieldBuilder()
+          .addBuilder(
+              index,
+              com.google.spanner.admin.database.v1.BackupInstancePartition.getDefaultInstance());
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Output only. The instance partition(s) storing the backup.
+     *
+     * This is the same as the list of the instance partition(s) that the database
+     * had footprint in at the backup's `version_time`.
+     * </pre>
+     *
+     * <code>
+     * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
+     */
+    public java.util.List<com.google.spanner.admin.database.v1.BackupInstancePartition.Builder>
+        getInstancePartitionsBuilderList() {
+      return getInstancePartitionsFieldBuilder().getBuilderList();
+    }
+
+    private com.google.protobuf.RepeatedFieldBuilderV3<
+            com.google.spanner.admin.database.v1.BackupInstancePartition,
+            com.google.spanner.admin.database.v1.BackupInstancePartition.Builder,
+            com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder>
+        getInstancePartitionsFieldBuilder() {
+      if (instancePartitionsBuilder_ == null) {
+        instancePartitionsBuilder_ =
+            new com.google.protobuf.RepeatedFieldBuilderV3<
+                com.google.spanner.admin.database.v1.BackupInstancePartition,
+                com.google.spanner.admin.database.v1.BackupInstancePartition.Builder,
+                com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder>(
+                instancePartitions_,
+                ((bitField0_ & 0x00040000) != 0),
+                getParentForChildren(),
+                isClean());
+        instancePartitions_ = null;
+      }
+      return instancePartitionsBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupInstancePartition.java b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupInstancePartition.java
new file mode 100644
index 00000000000..ad582b34807
--- /dev/null
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupInstancePartition.java
@@ -0,0 +1,637 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: google/spanner/admin/database/v1/backup.proto
+
+// Protobuf Java Version: 3.25.5
+package com.google.spanner.admin.database.v1;
+
+/**
+ *
+ *
+ * <pre>
+ * Instance partition information for the backup.
+ * </pre>
+ *
+ * Protobuf type {@code google.spanner.admin.database.v1.BackupInstancePartition}
+ */
+public final class BackupInstancePartition extends com.google.protobuf.GeneratedMessageV3
+    implements
+    // @@protoc_insertion_point(message_implements:google.spanner.admin.database.v1.BackupInstancePartition)
+    BackupInstancePartitionOrBuilder {
+  private static final long serialVersionUID = 0L;
+  // Use BackupInstancePartition.newBuilder() to construct.
+  private BackupInstancePartition(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+    super(builder);
+  }
+
+  private BackupInstancePartition() {
+    instancePartition_ = "";
+  }
+
+  @java.lang.Override
+  @SuppressWarnings({"unused"})
+  protected java.lang.Object newInstance(UnusedPrivateParameter unused) {
+    return new BackupInstancePartition();
+  }
+
+  public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
+    return com.google.spanner.admin.database.v1.BackupProto
+        .internal_static_google_spanner_admin_database_v1_BackupInstancePartition_descriptor;
+  }
+
+  @java.lang.Override
+  protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internalGetFieldAccessorTable() {
+    return com.google.spanner.admin.database.v1.BackupProto
+        .internal_static_google_spanner_admin_database_v1_BackupInstancePartition_fieldAccessorTable
+        .ensureFieldAccessorsInitialized(
+            com.google.spanner.admin.database.v1.BackupInstancePartition.class,
+            com.google.spanner.admin.database.v1.BackupInstancePartition.Builder.class);
+  }
+
+  public static final int INSTANCE_PARTITION_FIELD_NUMBER = 1;
+
+  @SuppressWarnings("serial")
+  private volatile java.lang.Object instancePartition_ = "";
+  /**
+   *
+   *
+   * <pre>
+   * A unique identifier for the instance partition. Values are of the form
+   * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+   * </pre>
+   *
+   * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+   *
+   * @return The instancePartition.
+   */
+  @java.lang.Override
+  public java.lang.String getInstancePartition() {
+    java.lang.Object ref = instancePartition_;
+    if (ref instanceof java.lang.String) {
+      return (java.lang.String) ref;
+    } else {
+      com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
+      java.lang.String s = bs.toStringUtf8();
+      instancePartition_ = s;
+      return s;
+    }
+  }
+  /**
+   *
+   *
+   * <pre>
+   * A unique identifier for the instance partition. Values are of the form
+   * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+   * </pre>
+   *
+   * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+   *
+   * @return The bytes for instancePartition.
+   */
+  @java.lang.Override
+  public com.google.protobuf.ByteString getInstancePartitionBytes() {
+    java.lang.Object ref = instancePartition_;
+    if (ref instanceof java.lang.String) {
+      com.google.protobuf.ByteString b =
+          com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
+      instancePartition_ = b;
+      return b;
+    } else {
+      return (com.google.protobuf.ByteString) ref;
+    }
+  }
+
+  private byte memoizedIsInitialized = -1;
+
+  @java.lang.Override
+  public final boolean isInitialized() {
+    byte isInitialized = memoizedIsInitialized;
+    if (isInitialized == 1) return true;
+    if (isInitialized == 0) return false;
+
+    memoizedIsInitialized = 1;
+    return true;
+  }
+
+  @java.lang.Override
+  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(instancePartition_)) {
+      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, instancePartition_);
+    }
+    getUnknownFields().writeTo(output);
+  }
+
+  @java.lang.Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) return size;
+
+    size = 0;
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(instancePartition_)) {
+      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(1, instancePartition_);
+    }
+    size += getUnknownFields().getSerializedSize();
+    memoizedSize = size;
+    return size;
+  }
+
+  @java.lang.Override
+  public boolean equals(final java.lang.Object obj) {
+    if (obj == this) {
+      return true;
+    }
+    if (!(obj instanceof com.google.spanner.admin.database.v1.BackupInstancePartition)) {
+      return super.equals(obj);
+    }
+    com.google.spanner.admin.database.v1.BackupInstancePartition other =
+        (com.google.spanner.admin.database.v1.BackupInstancePartition) obj;
+
+    if (!getInstancePartition().equals(other.getInstancePartition())) return false;
+    if (!getUnknownFields().equals(other.getUnknownFields())) return false;
+    return true;
+  }
+
+  @java.lang.Override
+  public int hashCode() {
+    if (memoizedHashCode != 0) {
+      return memoizedHashCode;
+    }
+    int hash = 41;
+    hash = (19 * hash) + getDescriptor().hashCode();
+    hash = (37 * hash) + INSTANCE_PARTITION_FIELD_NUMBER;
+    hash = (53 * hash) + getInstancePartition().hashCode();
+    hash = (29 * hash) + getUnknownFields().hashCode();
+    memoizedHashCode = hash;
+    return hash;
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      java.nio.ByteBuffer data) throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      java.nio.ByteBuffer data, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      com.google.protobuf.ByteString data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      com.google.protobuf.ByteString data,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(byte[] data)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      byte[] data, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws com.google.protobuf.InvalidProtocolBufferException {
+    return PARSER.parseFrom(data, extensionRegistry);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      java.io.InputStream input) throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(PARSER, input);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      java.io.InputStream input, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(
+        PARSER, input, extensionRegistry);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseDelimitedFrom(
+      java.io.InputStream input) throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseDelimitedWithIOException(PARSER, input);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseDelimitedFrom(
+      java.io.InputStream input, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseDelimitedWithIOException(
+        PARSER, input, extensionRegistry);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      com.google.protobuf.CodedInputStream input) throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(PARSER, input);
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition parseFrom(
+      com.google.protobuf.CodedInputStream input,
+      com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+      throws java.io.IOException {
+    return com.google.protobuf.GeneratedMessageV3.parseWithIOException(
+        PARSER, input, extensionRegistry);
+  }
+
+  @java.lang.Override
+  public Builder newBuilderForType() {
+    return newBuilder();
+  }
+
+  public static Builder newBuilder() {
+    return DEFAULT_INSTANCE.toBuilder();
+  }
+
+  public static Builder newBuilder(
+      com.google.spanner.admin.database.v1.BackupInstancePartition prototype) {
+    return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+  }
+
+  @java.lang.Override
+  public Builder toBuilder() {
+    return this == DEFAULT_INSTANCE ? new Builder() : new Builder().mergeFrom(this);
+  }
+
+  @java.lang.Override
+  protected Builder newBuilderForType(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+    Builder builder = new Builder(parent);
+    return builder;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Instance partition information for the backup.
+   * </pre>
+   *
+   * Protobuf type {@code google.spanner.admin.database.v1.BackupInstancePartition}
+   */
+  public static final class Builder extends com.google.protobuf.GeneratedMessageV3.Builder<Builder>
+      implements
+      // @@protoc_insertion_point(builder_implements:google.spanner.admin.database.v1.BackupInstancePartition)
+      com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder {
+    public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
+      return com.google.spanner.admin.database.v1.BackupProto
+          .internal_static_google_spanner_admin_database_v1_BackupInstancePartition_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return com.google.spanner.admin.database.v1.BackupProto
+          .internal_static_google_spanner_admin_database_v1_BackupInstancePartition_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              com.google.spanner.admin.database.v1.BackupInstancePartition.class,
+              com.google.spanner.admin.database.v1.BackupInstancePartition.Builder.class);
+    }
+
+    // Construct using com.google.spanner.admin.database.v1.BackupInstancePartition.newBuilder()
+    private Builder() {}
+
+    private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      super(parent);
+    }
+
+    @java.lang.Override
+    public Builder clear() {
+      super.clear();
+      bitField0_ = 0;
+      instancePartition_ = "";
+      return this;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Descriptors.Descriptor getDescriptorForType() {
+      return com.google.spanner.admin.database.v1.BackupProto
+          .internal_static_google_spanner_admin_database_v1_BackupInstancePartition_descriptor;
+    }
+
+    @java.lang.Override
+    public com.google.spanner.admin.database.v1.BackupInstancePartition
+        getDefaultInstanceForType() {
+      return com.google.spanner.admin.database.v1.BackupInstancePartition.getDefaultInstance();
+    }
+
+    @java.lang.Override
+    public com.google.spanner.admin.database.v1.BackupInstancePartition build() {
+      com.google.spanner.admin.database.v1.BackupInstancePartition result = buildPartial();
+      if (!result.isInitialized()) {
+        throw newUninitializedMessageException(result);
+      }
+      return result;
+    }
+
+    @java.lang.Override
+    public com.google.spanner.admin.database.v1.BackupInstancePartition buildPartial() {
+      com.google.spanner.admin.database.v1.BackupInstancePartition result =
+          new com.google.spanner.admin.database.v1.BackupInstancePartition(this);
+      if (bitField0_ != 0) {
+        buildPartial0(result);
+      }
+      onBuilt();
+      return result;
+    }
+
+    private void buildPartial0(
+        com.google.spanner.admin.database.v1.BackupInstancePartition result) {
+      int from_bitField0_ = bitField0_;
+      if (((from_bitField0_ & 0x00000001) != 0)) {
+        result.instancePartition_ = instancePartition_;
+      }
+    }
+
+    @java.lang.Override
+    public Builder clone() {
+      return super.clone();
+    }
+
+    @java.lang.Override
+    public Builder setField(
+        com.google.protobuf.Descriptors.FieldDescriptor field, java.lang.Object value) {
+      return super.setField(field, value);
+    }
+
+    @java.lang.Override
+    public Builder clearField(com.google.protobuf.Descriptors.FieldDescriptor field) {
+      return super.clearField(field);
+    }
+
+    @java.lang.Override
+    public Builder clearOneof(com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+      return super.clearOneof(oneof);
+    }
+
+    @java.lang.Override
+    public Builder setRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field, int index, java.lang.Object value) {
+      return super.setRepeatedField(field, index, value);
+    }
+
+    @java.lang.Override
+    public Builder addRepeatedField(
+        com.google.protobuf.Descriptors.FieldDescriptor field, java.lang.Object value) {
+      return super.addRepeatedField(field, value);
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(com.google.protobuf.Message other) {
+      if (other instanceof com.google.spanner.admin.database.v1.BackupInstancePartition) {
+        return mergeFrom((com.google.spanner.admin.database.v1.BackupInstancePartition) other);
+      } else {
+        super.mergeFrom(other);
+        return this;
+      }
+    }
+
+    public Builder mergeFrom(com.google.spanner.admin.database.v1.BackupInstancePartition other) {
+      if (other
+          == com.google.spanner.admin.database.v1.BackupInstancePartition.getDefaultInstance())
+        return this;
+      if (!other.getInstancePartition().isEmpty()) {
+        instancePartition_ = other.instancePartition_;
+        bitField0_ |= 0x00000001;
+        onChanged();
+      }
+      this.mergeUnknownFields(other.getUnknownFields());
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      return true;
+    }
+
+    @java.lang.Override
+    public Builder mergeFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
+      try {
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 10:
+              {
+                instancePartition_ = input.readStringRequireUtf8();
+                bitField0_ |= 0x00000001;
+                break;
+              } // case 10
+            default:
+              {
+                if (!super.parseUnknownField(input, extensionRegistry, tag)) {
+                  done = true; // was an endgroup tag
+                }
+                break;
+              } // default:
+          } // switch (tag)
+        } // while (!done)
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        throw e.unwrapIOException();
+      } finally {
+        onChanged();
+      } // finally
+      return this;
+    }
+
+    private int bitField0_;
+
+    private java.lang.Object instancePartition_ = "";
+    /**
+     *
+     *
+     * <pre>
+     * A unique identifier for the instance partition. Values are of the form
+     * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+     * </pre>
+     *
+     * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+     *
+     * @return The instancePartition.
+     */
+    public java.lang.String getInstancePartition() {
+      java.lang.Object ref = instancePartition_;
+      if (!(ref instanceof java.lang.String)) {
+        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
+        java.lang.String s = bs.toStringUtf8();
+        instancePartition_ = s;
+        return s;
+      } else {
+        return (java.lang.String) ref;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A unique identifier for the instance partition. Values are of the form
+     * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+     * </pre>
+     *
+     * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+     *
+     * @return The bytes for instancePartition.
+     */
+    public com.google.protobuf.ByteString getInstancePartitionBytes() {
+      java.lang.Object ref = instancePartition_;
+      if (ref instanceof String) {
+        com.google.protobuf.ByteString b =
+            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
+        instancePartition_ = b;
+        return b;
+      } else {
+        return (com.google.protobuf.ByteString) ref;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A unique identifier for the instance partition. Values are of the form
+     * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+     * </pre>
+     *
+     * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+     *
+     * @param value The instancePartition to set.
+     * @return This builder for chaining.
+     */
+    public Builder setInstancePartition(java.lang.String value) {
+      if (value == null) {
+        throw new NullPointerException();
+      }
+      instancePartition_ = value;
+      bitField0_ |= 0x00000001;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A unique identifier for the instance partition. Values are of the form
+     * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+     * </pre>
+     *
+     * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearInstancePartition() {
+      instancePartition_ = getDefaultInstance().getInstancePartition();
+      bitField0_ = (bitField0_ & ~0x00000001);
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * A unique identifier for the instance partition. Values are of the form
+     * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+     * </pre>
+     *
+     * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+     *
+     * @param value The bytes for instancePartition to set.
+     * @return This builder for chaining.
+     */
+    public Builder setInstancePartitionBytes(com.google.protobuf.ByteString value) {
+      if (value == null) {
+        throw new NullPointerException();
+      }
+      checkByteStringIsUtf8(value);
+      instancePartition_ = value;
+      bitField0_ |= 0x00000001;
+      onChanged();
+      return this;
+    }
+
+    @java.lang.Override
+    public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.setUnknownFields(unknownFields);
+    }
+
+    @java.lang.Override
+    public final Builder mergeUnknownFields(
+        final com.google.protobuf.UnknownFieldSet unknownFields) {
+      return super.mergeUnknownFields(unknownFields);
+    }
+
+    // @@protoc_insertion_point(builder_scope:google.spanner.admin.database.v1.BackupInstancePartition)
+  }
+
+  // @@protoc_insertion_point(class_scope:google.spanner.admin.database.v1.BackupInstancePartition)
+  private static final com.google.spanner.admin.database.v1.BackupInstancePartition
+      DEFAULT_INSTANCE;
+
+  static {
+    DEFAULT_INSTANCE = new com.google.spanner.admin.database.v1.BackupInstancePartition();
+  }
+
+  public static com.google.spanner.admin.database.v1.BackupInstancePartition getDefaultInstance() {
+    return DEFAULT_INSTANCE;
+  }
+
+  private static final com.google.protobuf.Parser<BackupInstancePartition> PARSER =
+      new com.google.protobuf.AbstractParser<BackupInstancePartition>() {
+        @java.lang.Override
+        public BackupInstancePartition parsePartialFrom(
+            com.google.protobuf.CodedInputStream input,
+            com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+            throws com.google.protobuf.InvalidProtocolBufferException {
+          Builder builder = newBuilder();
+          try {
+            builder.mergeFrom(input, extensionRegistry);
+          } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+            throw e.setUnfinishedMessage(builder.buildPartial());
+          } catch (com.google.protobuf.UninitializedMessageException e) {
+            throw e.asInvalidProtocolBufferException().setUnfinishedMessage(builder.buildPartial());
+          } catch (java.io.IOException e) {
+            throw new com.google.protobuf.InvalidProtocolBufferException(e)
+                .setUnfinishedMessage(builder.buildPartial());
+          }
+          return builder.buildPartial();
+        }
+      };
+
+  public static com.google.protobuf.Parser<BackupInstancePartition> parser() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.protobuf.Parser<BackupInstancePartition> getParserForType() {
+    return PARSER;
+  }
+
+  @java.lang.Override
+  public com.google.spanner.admin.database.v1.BackupInstancePartition getDefaultInstanceForType() {
+    return DEFAULT_INSTANCE;
+  }
+}
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupInstancePartitionOrBuilder.java b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupInstancePartitionOrBuilder.java
new file mode 100644
index 00000000000..eb1b19816b9
--- /dev/null
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupInstancePartitionOrBuilder.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: google/spanner/admin/database/v1/backup.proto
+
+// Protobuf Java Version: 3.25.5
+package com.google.spanner.admin.database.v1;
+
+public interface BackupInstancePartitionOrBuilder
+    extends
+    // @@protoc_insertion_point(interface_extends:google.spanner.admin.database.v1.BackupInstancePartition)
+    com.google.protobuf.MessageOrBuilder {
+
+  /**
+   *
+   *
+   * <pre>
+   * A unique identifier for the instance partition. Values are of the form
+   * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+   * </pre>
+   *
+   * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+   *
+   * @return The instancePartition.
+   */
+  java.lang.String getInstancePartition();
+  /**
+   *
+   *
+   * <pre>
+   * A unique identifier for the instance partition. Values are of the form
+   * `projects/&lt;project&gt;/instances/&lt;instance&gt;/instancePartitions/&lt;instance_partition_id&gt;`
+   * </pre>
+   *
+   * <code>string instance_partition = 1 [(.google.api.resource_reference) = { ... }</code>
+   *
+   * @return The bytes for instancePartition.
+   */
+  com.google.protobuf.ByteString getInstancePartitionBytes();
+}
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupOrBuilder.java b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupOrBuilder.java
index d30141d6fc3..eb90b03212d 100644
--- a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupOrBuilder.java
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupOrBuilder.java
@@ -895,4 +895,83 @@ com.google.spanner.admin.database.v1.EncryptionInfoOrBuilder getEncryptionInform
    * </code>
    */
   com.google.protobuf.TimestampOrBuilder getOldestVersionTimeOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  java.util.List<com.google.spanner.admin.database.v1.BackupInstancePartition>
+      getInstancePartitionsList();
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  com.google.spanner.admin.database.v1.BackupInstancePartition getInstancePartitions(int index);
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  int getInstancePartitionsCount();
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  java.util.List<? extends com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder>
+      getInstancePartitionsOrBuilderList();
+  /**
+   *
+   *
+   * <pre>
+   * Output only. The instance partition(s) storing the backup.
+   *
+   * This is the same as the list of the instance partition(s) that the database
+   * had footprint in at the backup's `version_time`.
+   * </pre>
+   *
+   * <code>
+   * repeated .google.spanner.admin.database.v1.BackupInstancePartition instance_partitions = 19 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
+   */
+  com.google.spanner.admin.database.v1.BackupInstancePartitionOrBuilder
+      getInstancePartitionsOrBuilder(int index);
 }
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupProto.java b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupProto.java
index 52bac0ab063..5f04fe540cc 100644
--- a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupProto.java
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/BackupProto.java
@@ -96,6 +96,10 @@ public static void registerAllExtensions(com.google.protobuf.ExtensionRegistry r
       internal_static_google_spanner_admin_database_v1_IncrementalBackupSpec_descriptor;
   static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
       internal_static_google_spanner_admin_database_v1_IncrementalBackupSpec_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+      internal_static_google_spanner_admin_database_v1_BackupInstancePartition_descriptor;
+  static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_google_spanner_admin_database_v1_BackupInstancePartition_fieldAccessorTable;
 
   public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
     return descriptor;
@@ -112,7 +116,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "g/operations.proto\032 google/protobuf/fiel"
           + "d_mask.proto\032\037google/protobuf/timestamp."
           + "proto\032-google/spanner/admin/database/v1/"
-          + "common.proto\"\220\t\n\006Backup\0226\n\010database\030\002 \001("
+          + "common.proto\"\355\t\n\006Backup\0226\n\010database\030\002 \001("
           + "\tB$\372A!\n\037spanner.googleapis.com/Database\022"
           + "0\n\014version_time\030\t \001(\0132\032.google.protobuf."
           + "Timestamp\022/\n\013expire_time\030\003 \001(\0132\032.google."
@@ -137,92 +141,97 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "\tB-\340A\003\372A\'\n%spanner.googleapis.com/Backup"
           + "Schedule\022(\n\033incremental_backup_chain_id\030"
           + "\021 \001(\tB\003\340A\003\022<\n\023oldest_version_time\030\022 \001(\0132"
-          + "\032.google.protobuf.TimestampB\003\340A\003\"7\n\005Stat"
-          + "e\022\025\n\021STATE_UNSPECIFIED\020\000\022\014\n\010CREATING\020\001\022\t"
-          + "\n\005READY\020\002:\\\352AY\n\035spanner.googleapis.com/B"
-          + "ackup\0228projects/{project}/instances/{ins"
-          + "tance}/backups/{backup}\"\205\002\n\023CreateBackup"
-          + "Request\0227\n\006parent\030\001 \001(\tB\'\340A\002\372A!\n\037spanner"
-          + ".googleapis.com/Instance\022\026\n\tbackup_id\030\002 "
-          + "\001(\tB\003\340A\002\022=\n\006backup\030\003 \001(\0132(.google.spanne"
-          + "r.admin.database.v1.BackupB\003\340A\002\022^\n\021encry"
-          + "ption_config\030\004 \001(\0132>.google.spanner.admi"
-          + "n.database.v1.CreateBackupEncryptionConf"
-          + "igB\003\340A\001\"\370\001\n\024CreateBackupMetadata\0220\n\004name"
-          + "\030\001 \001(\tB\"\372A\037\n\035spanner.googleapis.com/Back"
-          + "up\0226\n\010database\030\002 \001(\tB$\372A!\n\037spanner.googl"
-          + "eapis.com/Database\022E\n\010progress\030\003 \001(\01323.g"
-          + "oogle.spanner.admin.database.v1.Operatio"
-          + "nProgress\022/\n\013cancel_time\030\004 \001(\0132\032.google."
-          + "protobuf.Timestamp\"\266\002\n\021CopyBackupRequest"
+          + "\032.google.protobuf.TimestampB\003\340A\003\022[\n\023inst"
+          + "ance_partitions\030\023 \003(\01329.google.spanner.a"
+          + "dmin.database.v1.BackupInstancePartition"
+          + "B\003\340A\003\"7\n\005State\022\025\n\021STATE_UNSPECIFIED\020\000\022\014\n"
+          + "\010CREATING\020\001\022\t\n\005READY\020\002:\\\352AY\n\035spanner.goo"
+          + "gleapis.com/Backup\0228projects/{project}/i"
+          + "nstances/{instance}/backups/{backup}\"\205\002\n"
+          + "\023CreateBackupRequest\0227\n\006parent\030\001 \001(\tB\'\340A"
+          + "\002\372A!\n\037spanner.googleapis.com/Instance\022\026\n"
+          + "\tbackup_id\030\002 \001(\tB\003\340A\002\022=\n\006backup\030\003 \001(\0132(."
+          + "google.spanner.admin.database.v1.BackupB"
+          + "\003\340A\002\022^\n\021encryption_config\030\004 \001(\0132>.google"
+          + ".spanner.admin.database.v1.CreateBackupE"
+          + "ncryptionConfigB\003\340A\001\"\370\001\n\024CreateBackupMet"
+          + "adata\0220\n\004name\030\001 \001(\tB\"\372A\037\n\035spanner.google"
+          + "apis.com/Backup\0226\n\010database\030\002 \001(\tB$\372A!\n\037"
+          + "spanner.googleapis.com/Database\022E\n\010progr"
+          + "ess\030\003 \001(\01323.google.spanner.admin.databas"
+          + "e.v1.OperationProgress\022/\n\013cancel_time\030\004 "
+          + "\001(\0132\032.google.protobuf.Timestamp\"\266\002\n\021Copy"
+          + "BackupRequest\0227\n\006parent\030\001 \001(\tB\'\340A\002\372A!\n\037s"
+          + "panner.googleapis.com/Instance\022\026\n\tbackup"
+          + "_id\030\002 \001(\tB\003\340A\002\022<\n\rsource_backup\030\003 \001(\tB%\340"
+          + "A\002\372A\037\n\035spanner.googleapis.com/Backup\0224\n\013"
+          + "expire_time\030\004 \001(\0132\032.google.protobuf.Time"
+          + "stampB\003\340A\002\022\\\n\021encryption_config\030\005 \001(\0132<."
+          + "google.spanner.admin.database.v1.CopyBac"
+          + "kupEncryptionConfigB\003\340A\001\"\371\001\n\022CopyBackupM"
+          + "etadata\0220\n\004name\030\001 \001(\tB\"\372A\037\n\035spanner.goog"
+          + "leapis.com/Backup\0229\n\rsource_backup\030\002 \001(\t"
+          + "B\"\372A\037\n\035spanner.googleapis.com/Backup\022E\n\010"
+          + "progress\030\003 \001(\01323.google.spanner.admin.da"
+          + "tabase.v1.OperationProgress\022/\n\013cancel_ti"
+          + "me\030\004 \001(\0132\032.google.protobuf.Timestamp\"\212\001\n"
+          + "\023UpdateBackupRequest\022=\n\006backup\030\001 \001(\0132(.g"
+          + "oogle.spanner.admin.database.v1.BackupB\003"
+          + "\340A\002\0224\n\013update_mask\030\002 \001(\0132\032.google.protob"
+          + "uf.FieldMaskB\003\340A\002\"G\n\020GetBackupRequest\0223\n"
+          + "\004name\030\001 \001(\tB%\340A\002\372A\037\n\035spanner.googleapis."
+          + "com/Backup\"J\n\023DeleteBackupRequest\0223\n\004nam"
+          + "e\030\001 \001(\tB%\340A\002\372A\037\n\035spanner.googleapis.com/"
+          + "Backup\"\204\001\n\022ListBackupsRequest\0227\n\006parent\030"
+          + "\001 \001(\tB\'\340A\002\372A!\n\037spanner.googleapis.com/In"
+          + "stance\022\016\n\006filter\030\002 \001(\t\022\021\n\tpage_size\030\003 \001("
+          + "\005\022\022\n\npage_token\030\004 \001(\t\"i\n\023ListBackupsResp"
+          + "onse\0229\n\007backups\030\001 \003(\0132(.google.spanner.a"
+          + "dmin.database.v1.Backup\022\027\n\017next_page_tok"
+          + "en\030\002 \001(\t\"\215\001\n\033ListBackupOperationsRequest"
           + "\0227\n\006parent\030\001 \001(\tB\'\340A\002\372A!\n\037spanner.google"
-          + "apis.com/Instance\022\026\n\tbackup_id\030\002 \001(\tB\003\340A"
-          + "\002\022<\n\rsource_backup\030\003 \001(\tB%\340A\002\372A\037\n\035spanne"
-          + "r.googleapis.com/Backup\0224\n\013expire_time\030\004"
-          + " \001(\0132\032.google.protobuf.TimestampB\003\340A\002\022\\\n"
-          + "\021encryption_config\030\005 \001(\0132<.google.spanne"
-          + "r.admin.database.v1.CopyBackupEncryption"
-          + "ConfigB\003\340A\001\"\371\001\n\022CopyBackupMetadata\0220\n\004na"
-          + "me\030\001 \001(\tB\"\372A\037\n\035spanner.googleapis.com/Ba"
-          + "ckup\0229\n\rsource_backup\030\002 \001(\tB\"\372A\037\n\035spanne"
-          + "r.googleapis.com/Backup\022E\n\010progress\030\003 \001("
-          + "\01323.google.spanner.admin.database.v1.Ope"
-          + "rationProgress\022/\n\013cancel_time\030\004 \001(\0132\032.go"
-          + "ogle.protobuf.Timestamp\"\212\001\n\023UpdateBackup"
-          + "Request\022=\n\006backup\030\001 \001(\0132(.google.spanner"
-          + ".admin.database.v1.BackupB\003\340A\002\0224\n\013update"
-          + "_mask\030\002 \001(\0132\032.google.protobuf.FieldMaskB"
-          + "\003\340A\002\"G\n\020GetBackupRequest\0223\n\004name\030\001 \001(\tB%"
-          + "\340A\002\372A\037\n\035spanner.googleapis.com/Backup\"J\n"
-          + "\023DeleteBackupRequest\0223\n\004name\030\001 \001(\tB%\340A\002\372"
-          + "A\037\n\035spanner.googleapis.com/Backup\"\204\001\n\022Li"
-          + "stBackupsRequest\0227\n\006parent\030\001 \001(\tB\'\340A\002\372A!"
-          + "\n\037spanner.googleapis.com/Instance\022\016\n\006fil"
-          + "ter\030\002 \001(\t\022\021\n\tpage_size\030\003 \001(\005\022\022\n\npage_tok"
-          + "en\030\004 \001(\t\"i\n\023ListBackupsResponse\0229\n\007backu"
-          + "ps\030\001 \003(\0132(.google.spanner.admin.database"
-          + ".v1.Backup\022\027\n\017next_page_token\030\002 \001(\t\"\215\001\n\033"
-          + "ListBackupOperationsRequest\0227\n\006parent\030\001 "
-          + "\001(\tB\'\340A\002\372A!\n\037spanner.googleapis.com/Inst"
-          + "ance\022\016\n\006filter\030\002 \001(\t\022\021\n\tpage_size\030\003 \001(\005\022"
-          + "\022\n\npage_token\030\004 \001(\t\"j\n\034ListBackupOperati"
-          + "onsResponse\0221\n\noperations\030\001 \003(\0132\035.google"
-          + ".longrunning.Operation\022\027\n\017next_page_toke"
-          + "n\030\002 \001(\t\"\342\001\n\nBackupInfo\0222\n\006backup\030\001 \001(\tB\""
-          + "\372A\037\n\035spanner.googleapis.com/Backup\0220\n\014ve"
-          + "rsion_time\030\004 \001(\0132\032.google.protobuf.Times"
-          + "tamp\022/\n\013create_time\030\002 \001(\0132\032.google.proto"
-          + "buf.Timestamp\022=\n\017source_database\030\003 \001(\tB$"
-          + "\372A!\n\037spanner.googleapis.com/Database\"\237\003\n"
-          + "\034CreateBackupEncryptionConfig\022k\n\017encrypt"
-          + "ion_type\030\001 \001(\0162M.google.spanner.admin.da"
-          + "tabase.v1.CreateBackupEncryptionConfig.E"
-          + "ncryptionTypeB\003\340A\002\022?\n\014kms_key_name\030\002 \001(\t"
-          + "B)\340A\001\372A#\n!cloudkms.googleapis.com/Crypto"
-          + "Key\022@\n\rkms_key_names\030\003 \003(\tB)\340A\001\372A#\n!clou"
-          + "dkms.googleapis.com/CryptoKey\"\216\001\n\016Encryp"
-          + "tionType\022\037\n\033ENCRYPTION_TYPE_UNSPECIFIED\020"
-          + "\000\022\033\n\027USE_DATABASE_ENCRYPTION\020\001\022\035\n\031GOOGLE"
-          + "_DEFAULT_ENCRYPTION\020\002\022\037\n\033CUSTOMER_MANAGE"
-          + "D_ENCRYPTION\020\003\"\253\003\n\032CopyBackupEncryptionC"
-          + "onfig\022i\n\017encryption_type\030\001 \001(\0162K.google."
-          + "spanner.admin.database.v1.CopyBackupEncr"
-          + "yptionConfig.EncryptionTypeB\003\340A\002\022?\n\014kms_"
-          + "key_name\030\002 \001(\tB)\340A\001\372A#\n!cloudkms.googlea"
-          + "pis.com/CryptoKey\022@\n\rkms_key_names\030\003 \003(\t"
-          + "B)\340A\001\372A#\n!cloudkms.googleapis.com/Crypto"
-          + "Key\"\236\001\n\016EncryptionType\022\037\n\033ENCRYPTION_TYP"
-          + "E_UNSPECIFIED\020\000\022+\n\'USE_CONFIG_DEFAULT_OR"
-          + "_BACKUP_ENCRYPTION\020\001\022\035\n\031GOOGLE_DEFAULT_E"
-          + "NCRYPTION\020\002\022\037\n\033CUSTOMER_MANAGED_ENCRYPTI"
-          + "ON\020\003\"\020\n\016FullBackupSpec\"\027\n\025IncrementalBac"
-          + "kupSpecB\375\001\n$com.google.spanner.admin.dat"
-          + "abase.v1B\013BackupProtoP\001ZFcloud.google.co"
-          + "m/go/spanner/admin/database/apiv1/databa"
-          + "sepb;databasepb\252\002&Google.Cloud.Spanner.A"
-          + "dmin.Database.V1\312\002&Google\\Cloud\\Spanner\\"
-          + "Admin\\Database\\V1\352\002+Google::Cloud::Spann"
-          + "er::Admin::Database::V1b\006proto3"
+          + "apis.com/Instance\022\016\n\006filter\030\002 \001(\t\022\021\n\tpag"
+          + "e_size\030\003 \001(\005\022\022\n\npage_token\030\004 \001(\t\"j\n\034List"
+          + "BackupOperationsResponse\0221\n\noperations\030\001"
+          + " \003(\0132\035.google.longrunning.Operation\022\027\n\017n"
+          + "ext_page_token\030\002 \001(\t\"\342\001\n\nBackupInfo\0222\n\006b"
+          + "ackup\030\001 \001(\tB\"\372A\037\n\035spanner.googleapis.com"
+          + "/Backup\0220\n\014version_time\030\004 \001(\0132\032.google.p"
+          + "rotobuf.Timestamp\022/\n\013create_time\030\002 \001(\0132\032"
+          + ".google.protobuf.Timestamp\022=\n\017source_dat"
+          + "abase\030\003 \001(\tB$\372A!\n\037spanner.googleapis.com"
+          + "/Database\"\237\003\n\034CreateBackupEncryptionConf"
+          + "ig\022k\n\017encryption_type\030\001 \001(\0162M.google.spa"
+          + "nner.admin.database.v1.CreateBackupEncry"
+          + "ptionConfig.EncryptionTypeB\003\340A\002\022?\n\014kms_k"
+          + "ey_name\030\002 \001(\tB)\340A\001\372A#\n!cloudkms.googleap"
+          + "is.com/CryptoKey\022@\n\rkms_key_names\030\003 \003(\tB"
+          + ")\340A\001\372A#\n!cloudkms.googleapis.com/CryptoK"
+          + "ey\"\216\001\n\016EncryptionType\022\037\n\033ENCRYPTION_TYPE"
+          + "_UNSPECIFIED\020\000\022\033\n\027USE_DATABASE_ENCRYPTIO"
+          + "N\020\001\022\035\n\031GOOGLE_DEFAULT_ENCRYPTION\020\002\022\037\n\033CU"
+          + "STOMER_MANAGED_ENCRYPTION\020\003\"\253\003\n\032CopyBack"
+          + "upEncryptionConfig\022i\n\017encryption_type\030\001 "
+          + "\001(\0162K.google.spanner.admin.database.v1.C"
+          + "opyBackupEncryptionConfig.EncryptionType"
+          + "B\003\340A\002\022?\n\014kms_key_name\030\002 \001(\tB)\340A\001\372A#\n!clo"
+          + "udkms.googleapis.com/CryptoKey\022@\n\rkms_ke"
+          + "y_names\030\003 \003(\tB)\340A\001\372A#\n!cloudkms.googleap"
+          + "is.com/CryptoKey\"\236\001\n\016EncryptionType\022\037\n\033E"
+          + "NCRYPTION_TYPE_UNSPECIFIED\020\000\022+\n\'USE_CONF"
+          + "IG_DEFAULT_OR_BACKUP_ENCRYPTION\020\001\022\035\n\031GOO"
+          + "GLE_DEFAULT_ENCRYPTION\020\002\022\037\n\033CUSTOMER_MAN"
+          + "AGED_ENCRYPTION\020\003\"\020\n\016FullBackupSpec\"\027\n\025I"
+          + "ncrementalBackupSpec\"d\n\027BackupInstancePa"
+          + "rtition\022I\n\022instance_partition\030\001 \001(\tB-\372A*"
+          + "\n(spanner.googleapis.com/InstancePartiti"
+          + "onB\375\001\n$com.google.spanner.admin.database"
+          + ".v1B\013BackupProtoP\001ZFcloud.google.com/go/"
+          + "spanner/admin/database/apiv1/databasepb;"
+          + "databasepb\252\002&Google.Cloud.Spanner.Admin."
+          + "Database.V1\312\002&Google\\Cloud\\Spanner\\Admin"
+          + "\\Database\\V1\352\002+Google::Cloud::Spanner::A"
+          + "dmin::Database::V1b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
@@ -259,6 +268,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
               "BackupSchedules",
               "IncrementalBackupChainId",
               "OldestVersionTime",
+              "InstancePartitions",
             });
     internal_static_google_spanner_admin_database_v1_CreateBackupRequest_descriptor =
         getDescriptor().getMessageTypes().get(1);
@@ -384,6 +394,14 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_admin_database_v1_IncrementalBackupSpec_descriptor,
             new java.lang.String[] {});
+    internal_static_google_spanner_admin_database_v1_BackupInstancePartition_descriptor =
+        getDescriptor().getMessageTypes().get(17);
+    internal_static_google_spanner_admin_database_v1_BackupInstancePartition_fieldAccessorTable =
+        new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+            internal_static_google_spanner_admin_database_v1_BackupInstancePartition_descriptor,
+            new java.lang.String[] {
+              "InstancePartition",
+            });
     com.google.protobuf.ExtensionRegistry registry =
         com.google.protobuf.ExtensionRegistry.newInstance();
     registry.add(com.google.api.FieldBehaviorProto.fieldBehavior);
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/SpannerDatabaseAdminProto.java b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/SpannerDatabaseAdminProto.java
index 06a130a7002..7b9974f3e76 100644
--- a/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/SpannerDatabaseAdminProto.java
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/java/com/google/spanner/admin/database/v1/SpannerDatabaseAdminProto.java
@@ -461,7 +461,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "ackupSchedules\032x\312A\026spanner.googleapis.co"
           + "m\322A\\https://www.googleapis.com/auth/clou"
           + "d-platform,https://www.googleapis.com/au"
-          + "th/spanner.adminB\330\002\n$com.google.spanner."
+          + "th/spanner.adminB\326\003\n$com.google.spanner."
           + "admin.database.v1B\031SpannerDatabaseAdminP"
           + "rotoP\001ZFcloud.google.com/go/spanner/admi"
           + "n/database/apiv1/databasepb;databasepb\252\002"
@@ -470,7 +470,10 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "\352\002+Google::Cloud::Spanner::Admin::Databa"
           + "se::V1\352AJ\n\037spanner.googleapis.com/Instan"
           + "ce\022\'projects/{project}/instances/{instan"
-          + "ce}b\006proto3"
+          + "ce}\352A{\n(spanner.googleapis.com/InstanceP"
+          + "artition\022Oprojects/{project}/instances/{"
+          + "instance}/instancePartitions/{instance_p"
+          + "artition}b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/backup.proto b/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/backup.proto
index f3473f4eabf..54a7be3e33d 100644
--- a/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/backup.proto
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/backup.proto
@@ -207,6 +207,13 @@ message Backup {
   // retained by the backup system.
   google.protobuf.Timestamp oldest_version_time = 18
       [(google.api.field_behavior) = OUTPUT_ONLY];
+
+  // Output only. The instance partition(s) storing the backup.
+  //
+  // This is the same as the list of the instance partition(s) that the database
+  // had footprint in at the backup's `version_time`.
+  repeated BackupInstancePartition instance_partitions = 19
+      [(google.api.field_behavior) = OUTPUT_ONLY];
 }
 
 // The request for
@@ -755,3 +762,12 @@ message FullBackupSpec {}
 // successive incremental backups. The first backup created for an
 // incremental backup chain is always a full backup.
 message IncrementalBackupSpec {}
+
+// Instance partition information for the backup.
+message BackupInstancePartition {
+  // A unique identifier for the instance partition. Values are of the form
+  // `projects/<project>/instances/<instance>/instancePartitions/<instance_partition_id>`
+  string instance_partition = 1 [(google.api.resource_reference) = {
+    type: "spanner.googleapis.com/InstancePartition"
+  }];
+}
diff --git a/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/spanner_database_admin.proto b/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/spanner_database_admin.proto
index 27e3206293e..125196fe9bf 100644
--- a/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/spanner_database_admin.proto
+++ b/proto-google-cloud-spanner-admin-database-v1/src/main/proto/google/spanner/admin/database/v1/spanner_database_admin.proto
@@ -42,6 +42,10 @@ option (google.api.resource_definition) = {
   type: "spanner.googleapis.com/Instance"
   pattern: "projects/{project}/instances/{instance}"
 };
+option (google.api.resource_definition) = {
+  type: "spanner.googleapis.com/InstancePartition"
+  pattern: "projects/{project}/instances/{instance}/instancePartitions/{instance_partition}"
+};
 
 // Cloud Spanner Database Admin API
 //
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
index a12a8ebdb42..25e1a63c58f 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
@@ -361,7 +361,9 @@ private TransactionOptions(com.google.protobuf.GeneratedMessageV3.Builder<?> bui
     super(builder);
   }
 
-  private TransactionOptions() {}
+  private TransactionOptions() {
+    isolationLevel_ = 0;
+  }
 
   @java.lang.Override
   @SuppressWarnings({"unused"})
@@ -384,6 +386,203 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
             com.google.spanner.v1.TransactionOptions.Builder.class);
   }
 
+  /**
+   *
+   *
+   * <pre>
+   * `IsolationLevel` is used when setting `isolation_level` for a transaction.
+   * </pre>
+   *
+   * Protobuf enum {@code google.spanner.v1.TransactionOptions.IsolationLevel}
+   */
+  public enum IsolationLevel implements com.google.protobuf.ProtocolMessageEnum {
+    /**
+     *
+     *
+     * <pre>
+     * Default value.
+     *
+     * If the value is not specified, the `SERIALIZABLE` isolation level is
+     * used.
+     * </pre>
+     *
+     * <code>ISOLATION_LEVEL_UNSPECIFIED = 0;</code>
+     */
+    ISOLATION_LEVEL_UNSPECIFIED(0),
+    /**
+     *
+     *
+     * <pre>
+     * All transactions appear as if they executed in a serial order, even if
+     * some of the reads, writes, and other operations of distinct transactions
+     * actually occurred in parallel. Spanner assigns commit timestamps that
+     * reflect the order of committed transactions to implement this property.
+     * Spanner offers a stronger guarantee than serializability called external
+     * consistency. For further details, please refer to
+     * https://cloud.google.com/spanner/docs/true-time-external-consistency#serializability.
+     * </pre>
+     *
+     * <code>SERIALIZABLE = 1;</code>
+     */
+    SERIALIZABLE(1),
+    /**
+     *
+     *
+     * <pre>
+     * All reads performed during the transaction observe a consistent snapshot
+     * of the database, and the transaction will only successfully commit in the
+     * absence of conflicts between its updates and any concurrent updates that
+     * have occurred since that snapshot. Consequently, in contrast to
+     * `SERIALIZABLE` transactions, only write-write conflicts are detected in
+     * snapshot transactions.
+     *
+     * This isolation level does not support Read-only and Partitioned DML
+     * transactions.
+     *
+     * When `REPEATABLE_READ` is specified on a read-write transaction, the
+     * locking semantics default to `OPTIMISTIC`.
+     * </pre>
+     *
+     * <code>REPEATABLE_READ = 2;</code>
+     */
+    REPEATABLE_READ(2),
+    UNRECOGNIZED(-1),
+    ;
+
+    /**
+     *
+     *
+     * <pre>
+     * Default value.
+     *
+     * If the value is not specified, the `SERIALIZABLE` isolation level is
+     * used.
+     * </pre>
+     *
+     * <code>ISOLATION_LEVEL_UNSPECIFIED = 0;</code>
+     */
+    public static final int ISOLATION_LEVEL_UNSPECIFIED_VALUE = 0;
+    /**
+     *
+     *
+     * <pre>
+     * All transactions appear as if they executed in a serial order, even if
+     * some of the reads, writes, and other operations of distinct transactions
+     * actually occurred in parallel. Spanner assigns commit timestamps that
+     * reflect the order of committed transactions to implement this property.
+     * Spanner offers a stronger guarantee than serializability called external
+     * consistency. For further details, please refer to
+     * https://cloud.google.com/spanner/docs/true-time-external-consistency#serializability.
+     * </pre>
+     *
+     * <code>SERIALIZABLE = 1;</code>
+     */
+    public static final int SERIALIZABLE_VALUE = 1;
+    /**
+     *
+     *
+     * <pre>
+     * All reads performed during the transaction observe a consistent snapshot
+     * of the database, and the transaction will only successfully commit in the
+     * absence of conflicts between its updates and any concurrent updates that
+     * have occurred since that snapshot. Consequently, in contrast to
+     * `SERIALIZABLE` transactions, only write-write conflicts are detected in
+     * snapshot transactions.
+     *
+     * This isolation level does not support Read-only and Partitioned DML
+     * transactions.
+     *
+     * When `REPEATABLE_READ` is specified on a read-write transaction, the
+     * locking semantics default to `OPTIMISTIC`.
+     * </pre>
+     *
+     * <code>REPEATABLE_READ = 2;</code>
+     */
+    public static final int REPEATABLE_READ_VALUE = 2;
+
+    public final int getNumber() {
+      if (this == UNRECOGNIZED) {
+        throw new java.lang.IllegalArgumentException(
+            "Can't get the number of an unknown enum value.");
+      }
+      return value;
+    }
+
+    /**
+     * @param value The numeric wire value of the corresponding enum entry.
+     * @return The enum associated with the given numeric wire value.
+     * @deprecated Use {@link #forNumber(int)} instead.
+     */
+    @java.lang.Deprecated
+    public static IsolationLevel valueOf(int value) {
+      return forNumber(value);
+    }
+
+    /**
+     * @param value The numeric wire value of the corresponding enum entry.
+     * @return The enum associated with the given numeric wire value.
+     */
+    public static IsolationLevel forNumber(int value) {
+      switch (value) {
+        case 0:
+          return ISOLATION_LEVEL_UNSPECIFIED;
+        case 1:
+          return SERIALIZABLE;
+        case 2:
+          return REPEATABLE_READ;
+        default:
+          return null;
+      }
+    }
+
+    public static com.google.protobuf.Internal.EnumLiteMap<IsolationLevel> internalGetValueMap() {
+      return internalValueMap;
+    }
+
+    private static final com.google.protobuf.Internal.EnumLiteMap<IsolationLevel> internalValueMap =
+        new com.google.protobuf.Internal.EnumLiteMap<IsolationLevel>() {
+          public IsolationLevel findValueByNumber(int number) {
+            return IsolationLevel.forNumber(number);
+          }
+        };
+
+    public final com.google.protobuf.Descriptors.EnumValueDescriptor getValueDescriptor() {
+      if (this == UNRECOGNIZED) {
+        throw new java.lang.IllegalStateException(
+            "Can't get the descriptor of an unrecognized enum value.");
+      }
+      return getDescriptor().getValues().get(ordinal());
+    }
+
+    public final com.google.protobuf.Descriptors.EnumDescriptor getDescriptorForType() {
+      return getDescriptor();
+    }
+
+    public static final com.google.protobuf.Descriptors.EnumDescriptor getDescriptor() {
+      return com.google.spanner.v1.TransactionOptions.getDescriptor().getEnumTypes().get(0);
+    }
+
+    private static final IsolationLevel[] VALUES = values();
+
+    public static IsolationLevel valueOf(com.google.protobuf.Descriptors.EnumValueDescriptor desc) {
+      if (desc.getType() != getDescriptor()) {
+        throw new java.lang.IllegalArgumentException("EnumValueDescriptor is not for this type.");
+      }
+      if (desc.getIndex() == -1) {
+        return UNRECOGNIZED;
+      }
+      return VALUES[desc.getIndex()];
+    }
+
+    private final int value;
+
+    private IsolationLevel(int value) {
+      this.value = value;
+    }
+
+    // @@protoc_insertion_point(enum_scope:google.spanner.v1.TransactionOptions.IsolationLevel)
+  }
+
   public interface ReadWriteOrBuilder
       extends
       // @@protoc_insertion_point(interface_extends:google.spanner.v1.TransactionOptions.ReadWrite)
@@ -496,7 +695,17 @@ public enum ReadLockMode implements com.google.protobuf.ProtocolMessageEnum {
        * <pre>
        * Default value.
        *
-       * If the value is not specified, the pessimistic read lock is used.
+       * * If isolation level is `REPEATABLE_READ`, then it is an error to
+       *   specify `read_lock_mode`. Locking semantics default to `OPTIMISTIC`.
+       *   No validation checks are done for reads, except for:
+       *     1. reads done as part of queries that use `SELECT FOR UPDATE`
+       *     2. reads done as part of statements with a `LOCK_SCANNED_RANGES`
+       *        hint
+       *     3. reads done as part of DML statements
+       *   to validate that the data that was served at the snapshot time is
+       *   unchanged at commit time.
+       * * At all other isolation levels, if `read_lock_mode` is the default
+       *   value, then pessimistic read lock is used.
        * </pre>
        *
        * <code>READ_LOCK_MODE_UNSPECIFIED = 0;</code>
@@ -509,6 +718,7 @@ public enum ReadLockMode implements com.google.protobuf.ProtocolMessageEnum {
        * Pessimistic lock mode.
        *
        * Read locks are acquired immediately on read.
+       * Semantics described only applies to `SERIALIZABLE` isolation.
        * </pre>
        *
        * <code>PESSIMISTIC = 1;</code>
@@ -523,6 +733,7 @@ public enum ReadLockMode implements com.google.protobuf.ProtocolMessageEnum {
        * Locks for reads within the transaction are not acquired on read.
        * Instead the locks are acquired on a commit to validate that
        * read/queried data has not changed since the transaction started.
+       * Semantics described only applies to `SERIALIZABLE` isolation.
        * </pre>
        *
        * <code>OPTIMISTIC = 2;</code>
@@ -537,7 +748,17 @@ public enum ReadLockMode implements com.google.protobuf.ProtocolMessageEnum {
        * <pre>
        * Default value.
        *
-       * If the value is not specified, the pessimistic read lock is used.
+       * * If isolation level is `REPEATABLE_READ`, then it is an error to
+       *   specify `read_lock_mode`. Locking semantics default to `OPTIMISTIC`.
+       *   No validation checks are done for reads, except for:
+       *     1. reads done as part of queries that use `SELECT FOR UPDATE`
+       *     2. reads done as part of statements with a `LOCK_SCANNED_RANGES`
+       *        hint
+       *     3. reads done as part of DML statements
+       *   to validate that the data that was served at the snapshot time is
+       *   unchanged at commit time.
+       * * At all other isolation levels, if `read_lock_mode` is the default
+       *   value, then pessimistic read lock is used.
        * </pre>
        *
        * <code>READ_LOCK_MODE_UNSPECIFIED = 0;</code>
@@ -550,6 +771,7 @@ public enum ReadLockMode implements com.google.protobuf.ProtocolMessageEnum {
        * Pessimistic lock mode.
        *
        * Read locks are acquired immediately on read.
+       * Semantics described only applies to `SERIALIZABLE` isolation.
        * </pre>
        *
        * <code>PESSIMISTIC = 1;</code>
@@ -564,6 +786,7 @@ public enum ReadLockMode implements com.google.protobuf.ProtocolMessageEnum {
        * Locks for reads within the transaction are not acquired on read.
        * Instead the locks are acquired on a commit to validate that
        * read/queried data has not changed since the transaction started.
+       * Semantics described only applies to `SERIALIZABLE` isolation.
        * </pre>
        *
        * <code>OPTIMISTIC = 2;</code>
@@ -4777,6 +5000,43 @@ public boolean getExcludeTxnFromChangeStreams() {
     return excludeTxnFromChangeStreams_;
   }
 
+  public static final int ISOLATION_LEVEL_FIELD_NUMBER = 6;
+  private int isolationLevel_ = 0;
+  /**
+   *
+   *
+   * <pre>
+   * Isolation level for the transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+   *
+   * @return The enum numeric value on the wire for isolationLevel.
+   */
+  @java.lang.Override
+  public int getIsolationLevelValue() {
+    return isolationLevel_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Isolation level for the transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+   *
+   * @return The isolationLevel.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.TransactionOptions.IsolationLevel getIsolationLevel() {
+    com.google.spanner.v1.TransactionOptions.IsolationLevel result =
+        com.google.spanner.v1.TransactionOptions.IsolationLevel.forNumber(isolationLevel_);
+    return result == null
+        ? com.google.spanner.v1.TransactionOptions.IsolationLevel.UNRECOGNIZED
+        : result;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -4803,6 +5063,11 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (excludeTxnFromChangeStreams_ != false) {
       output.writeBool(5, excludeTxnFromChangeStreams_);
     }
+    if (isolationLevel_
+        != com.google.spanner.v1.TransactionOptions.IsolationLevel.ISOLATION_LEVEL_UNSPECIFIED
+            .getNumber()) {
+      output.writeEnum(6, isolationLevel_);
+    }
     getUnknownFields().writeTo(output);
   }
 
@@ -4831,6 +5096,11 @@ public int getSerializedSize() {
       size +=
           com.google.protobuf.CodedOutputStream.computeBoolSize(5, excludeTxnFromChangeStreams_);
     }
+    if (isolationLevel_
+        != com.google.spanner.v1.TransactionOptions.IsolationLevel.ISOLATION_LEVEL_UNSPECIFIED
+            .getNumber()) {
+      size += com.google.protobuf.CodedOutputStream.computeEnumSize(6, isolationLevel_);
+    }
     size += getUnknownFields().getSerializedSize();
     memoizedSize = size;
     return size;
@@ -4847,6 +5117,7 @@ public boolean equals(final java.lang.Object obj) {
     com.google.spanner.v1.TransactionOptions other = (com.google.spanner.v1.TransactionOptions) obj;
 
     if (getExcludeTxnFromChangeStreams() != other.getExcludeTxnFromChangeStreams()) return false;
+    if (isolationLevel_ != other.isolationLevel_) return false;
     if (!getModeCase().equals(other.getModeCase())) return false;
     switch (modeCase_) {
       case 1:
@@ -4874,6 +5145,8 @@ public int hashCode() {
     hash = (19 * hash) + getDescriptor().hashCode();
     hash = (37 * hash) + EXCLUDE_TXN_FROM_CHANGE_STREAMS_FIELD_NUMBER;
     hash = (53 * hash) + com.google.protobuf.Internal.hashBoolean(getExcludeTxnFromChangeStreams());
+    hash = (37 * hash) + ISOLATION_LEVEL_FIELD_NUMBER;
+    hash = (53 * hash) + isolationLevel_;
     switch (modeCase_) {
       case 1:
         hash = (37 * hash) + READ_WRITE_FIELD_NUMBER;
@@ -5362,6 +5635,7 @@ public Builder clear() {
         readOnlyBuilder_.clear();
       }
       excludeTxnFromChangeStreams_ = false;
+      isolationLevel_ = 0;
       modeCase_ = 0;
       mode_ = null;
       return this;
@@ -5404,6 +5678,9 @@ private void buildPartial0(com.google.spanner.v1.TransactionOptions result) {
       if (((from_bitField0_ & 0x00000008) != 0)) {
         result.excludeTxnFromChangeStreams_ = excludeTxnFromChangeStreams_;
       }
+      if (((from_bitField0_ & 0x00000010) != 0)) {
+        result.isolationLevel_ = isolationLevel_;
+      }
     }
 
     private void buildPartialOneofs(com.google.spanner.v1.TransactionOptions result) {
@@ -5468,6 +5745,9 @@ public Builder mergeFrom(com.google.spanner.v1.TransactionOptions other) {
       if (other.getExcludeTxnFromChangeStreams() != false) {
         setExcludeTxnFromChangeStreams(other.getExcludeTxnFromChangeStreams());
       }
+      if (other.isolationLevel_ != 0) {
+        setIsolationLevelValue(other.getIsolationLevelValue());
+      }
       switch (other.getModeCase()) {
         case READ_WRITE:
           {
@@ -5539,6 +5819,12 @@ public Builder mergeFrom(
                 bitField0_ |= 0x00000008;
                 break;
               } // case 40
+            case 48:
+              {
+                isolationLevel_ = input.readEnum();
+                bitField0_ |= 0x00000010;
+                break;
+              } // case 48
             default:
               {
                 if (!super.parseUnknownField(input, extensionRegistry, tag)) {
@@ -6404,6 +6690,99 @@ public Builder clearExcludeTxnFromChangeStreams() {
       return this;
     }
 
+    private int isolationLevel_ = 0;
+    /**
+     *
+     *
+     * <pre>
+     * Isolation level for the transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+     *
+     * @return The enum numeric value on the wire for isolationLevel.
+     */
+    @java.lang.Override
+    public int getIsolationLevelValue() {
+      return isolationLevel_;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Isolation level for the transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+     *
+     * @param value The enum numeric value on the wire for isolationLevel to set.
+     * @return This builder for chaining.
+     */
+    public Builder setIsolationLevelValue(int value) {
+      isolationLevel_ = value;
+      bitField0_ |= 0x00000010;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Isolation level for the transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+     *
+     * @return The isolationLevel.
+     */
+    @java.lang.Override
+    public com.google.spanner.v1.TransactionOptions.IsolationLevel getIsolationLevel() {
+      com.google.spanner.v1.TransactionOptions.IsolationLevel result =
+          com.google.spanner.v1.TransactionOptions.IsolationLevel.forNumber(isolationLevel_);
+      return result == null
+          ? com.google.spanner.v1.TransactionOptions.IsolationLevel.UNRECOGNIZED
+          : result;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Isolation level for the transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+     *
+     * @param value The isolationLevel to set.
+     * @return This builder for chaining.
+     */
+    public Builder setIsolationLevel(
+        com.google.spanner.v1.TransactionOptions.IsolationLevel value) {
+      if (value == null) {
+        throw new NullPointerException();
+      }
+      bitField0_ |= 0x00000010;
+      isolationLevel_ = value.getNumber();
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Isolation level for the transaction.
+     * </pre>
+     *
+     * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearIsolationLevel() {
+      bitField0_ = (bitField0_ & ~0x00000010);
+      isolationLevel_ = 0;
+      onChanged();
+      return this;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptionsOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptionsOrBuilder.java
index fff95012eed..07566e10592 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptionsOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptionsOrBuilder.java
@@ -191,5 +191,30 @@ public interface TransactionOptionsOrBuilder
    */
   boolean getExcludeTxnFromChangeStreams();
 
+  /**
+   *
+   *
+   * <pre>
+   * Isolation level for the transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+   *
+   * @return The enum numeric value on the wire for isolationLevel.
+   */
+  int getIsolationLevelValue();
+  /**
+   *
+   *
+   * <pre>
+   * Isolation level for the transaction.
+   * </pre>
+   *
+   * <code>.google.spanner.v1.TransactionOptions.IsolationLevel isolation_level = 6;</code>
+   *
+   * @return The isolationLevel.
+   */
+  com.google.spanner.v1.TransactionOptions.IsolationLevel getIsolationLevel();
+
   com.google.spanner.v1.TransactionOptions.ModeCase getModeCase();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java
index 4e94598f9b1..7c8b6760bdc 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionProto.java
@@ -68,43 +68,48 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
       "\n#google/spanner/v1/transaction.proto\022\021g"
           + "oogle.spanner.v1\032\037google/api/field_behav"
           + "ior.proto\032\036google/protobuf/duration.prot"
-          + "o\032\037google/protobuf/timestamp.proto\"\316\006\n\022T"
+          + "o\032\037google/protobuf/timestamp.proto\"\367\007\n\022T"
           + "ransactionOptions\022E\n\nread_write\030\001 \001(\0132/."
           + "google.spanner.v1.TransactionOptions.Rea"
           + "dWriteH\000\022O\n\017partitioned_dml\030\003 \001(\01324.goog"
           + "le.spanner.v1.TransactionOptions.Partiti"
           + "onedDmlH\000\022C\n\tread_only\030\002 \001(\0132..google.sp"
           + "anner.v1.TransactionOptions.ReadOnlyH\000\022\'"
-          + "\n\037exclude_txn_from_change_streams\030\005 \001(\010\032"
-          + "\354\001\n\tReadWrite\022T\n\016read_lock_mode\030\001 \001(\0162<."
-          + "google.spanner.v1.TransactionOptions.Rea"
-          + "dWrite.ReadLockMode\0228\n+multiplexed_sessi"
-          + "on_previous_transaction_id\030\002 \001(\014B\003\340A\001\"O\n"
-          + "\014ReadLockMode\022\036\n\032READ_LOCK_MODE_UNSPECIF"
-          + "IED\020\000\022\017\n\013PESSIMISTIC\020\001\022\016\n\nOPTIMISTIC\020\002\032\020"
-          + "\n\016PartitionedDml\032\250\002\n\010ReadOnly\022\020\n\006strong\030"
-          + "\001 \001(\010H\000\0228\n\022min_read_timestamp\030\002 \001(\0132\032.go"
-          + "ogle.protobuf.TimestampH\000\0222\n\rmax_stalene"
-          + "ss\030\003 \001(\0132\031.google.protobuf.DurationH\000\0224\n"
-          + "\016read_timestamp\030\004 \001(\0132\032.google.protobuf."
-          + "TimestampH\000\0224\n\017exact_staleness\030\005 \001(\0132\031.g"
-          + "oogle.protobuf.DurationH\000\022\035\n\025return_read"
-          + "_timestamp\030\006 \001(\010B\021\n\017timestamp_boundB\006\n\004m"
-          + "ode\"\233\001\n\013Transaction\022\n\n\002id\030\001 \001(\014\0222\n\016read_"
-          + "timestamp\030\002 \001(\0132\032.google.protobuf.Timest"
-          + "amp\022L\n\017precommit_token\030\003 \001(\01323.google.sp"
-          + "anner.v1.MultiplexedSessionPrecommitToke"
-          + "n\"\244\001\n\023TransactionSelector\022;\n\nsingle_use\030"
-          + "\001 \001(\0132%.google.spanner.v1.TransactionOpt"
-          + "ionsH\000\022\014\n\002id\030\002 \001(\014H\000\0226\n\005begin\030\003 \001(\0132%.go"
-          + "ogle.spanner.v1.TransactionOptionsH\000B\n\n\010"
-          + "selector\"L\n MultiplexedSessionPrecommitT"
-          + "oken\022\027\n\017precommit_token\030\001 \001(\014\022\017\n\007seq_num"
-          + "\030\002 \001(\005B\263\001\n\025com.google.spanner.v1B\020Transa"
-          + "ctionProtoP\001Z5cloud.google.com/go/spanne"
-          + "r/apiv1/spannerpb;spannerpb\252\002\027Google.Clo"
-          + "ud.Spanner.V1\312\002\027Google\\Cloud\\Spanner\\V1\352"
-          + "\002\032Google::Cloud::Spanner::V1b\006proto3"
+          + "\n\037exclude_txn_from_change_streams\030\005 \001(\010\022"
+          + "M\n\017isolation_level\030\006 \001(\01624.google.spanne"
+          + "r.v1.TransactionOptions.IsolationLevel\032\354"
+          + "\001\n\tReadWrite\022T\n\016read_lock_mode\030\001 \001(\0162<.g"
+          + "oogle.spanner.v1.TransactionOptions.Read"
+          + "Write.ReadLockMode\0228\n+multiplexed_sessio"
+          + "n_previous_transaction_id\030\002 \001(\014B\003\340A\001\"O\n\014"
+          + "ReadLockMode\022\036\n\032READ_LOCK_MODE_UNSPECIFI"
+          + "ED\020\000\022\017\n\013PESSIMISTIC\020\001\022\016\n\nOPTIMISTIC\020\002\032\020\n"
+          + "\016PartitionedDml\032\250\002\n\010ReadOnly\022\020\n\006strong\030\001"
+          + " \001(\010H\000\0228\n\022min_read_timestamp\030\002 \001(\0132\032.goo"
+          + "gle.protobuf.TimestampH\000\0222\n\rmax_stalenes"
+          + "s\030\003 \001(\0132\031.google.protobuf.DurationH\000\0224\n\016"
+          + "read_timestamp\030\004 \001(\0132\032.google.protobuf.T"
+          + "imestampH\000\0224\n\017exact_staleness\030\005 \001(\0132\031.go"
+          + "ogle.protobuf.DurationH\000\022\035\n\025return_read_"
+          + "timestamp\030\006 \001(\010B\021\n\017timestamp_bound\"X\n\016Is"
+          + "olationLevel\022\037\n\033ISOLATION_LEVEL_UNSPECIF"
+          + "IED\020\000\022\020\n\014SERIALIZABLE\020\001\022\023\n\017REPEATABLE_RE"
+          + "AD\020\002B\006\n\004mode\"\233\001\n\013Transaction\022\n\n\002id\030\001 \001(\014"
+          + "\0222\n\016read_timestamp\030\002 \001(\0132\032.google.protob"
+          + "uf.Timestamp\022L\n\017precommit_token\030\003 \001(\01323."
+          + "google.spanner.v1.MultiplexedSessionPrec"
+          + "ommitToken\"\244\001\n\023TransactionSelector\022;\n\nsi"
+          + "ngle_use\030\001 \001(\0132%.google.spanner.v1.Trans"
+          + "actionOptionsH\000\022\014\n\002id\030\002 \001(\014H\000\0226\n\005begin\030\003"
+          + " \001(\0132%.google.spanner.v1.TransactionOpti"
+          + "onsH\000B\n\n\010selector\"L\n MultiplexedSessionP"
+          + "recommitToken\022\027\n\017precommit_token\030\001 \001(\014\022\017"
+          + "\n\007seq_num\030\002 \001(\005B\263\001\n\025com.google.spanner.v"
+          + "1B\020TransactionProtoP\001Z5cloud.google.com/"
+          + "go/spanner/apiv1/spannerpb;spannerpb\252\002\027G"
+          + "oogle.Cloud.Spanner.V1\312\002\027Google\\Cloud\\Sp"
+          + "anner\\V1\352\002\032Google::Cloud::Spanner::V1b\006p"
+          + "roto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
@@ -120,7 +125,12 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_TransactionOptions_descriptor,
             new java.lang.String[] {
-              "ReadWrite", "PartitionedDml", "ReadOnly", "ExcludeTxnFromChangeStreams", "Mode",
+              "ReadWrite",
+              "PartitionedDml",
+              "ReadOnly",
+              "ExcludeTxnFromChangeStreams",
+              "IsolationLevel",
+              "Mode",
             });
     internal_static_google_spanner_v1_TransactionOptions_ReadWrite_descriptor =
         internal_static_google_spanner_v1_TransactionOptions_descriptor.getNestedTypes().get(0);
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
index fe564538466..dced12c1093 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
@@ -361,12 +361,23 @@ message TransactionOptions {
     enum ReadLockMode {
       // Default value.
       //
-      // If the value is not specified, the pessimistic read lock is used.
+      // * If isolation level is `REPEATABLE_READ`, then it is an error to
+      //   specify `read_lock_mode`. Locking semantics default to `OPTIMISTIC`.
+      //   No validation checks are done for reads, except for:
+      //     1. reads done as part of queries that use `SELECT FOR UPDATE`
+      //     2. reads done as part of statements with a `LOCK_SCANNED_RANGES`
+      //        hint
+      //     3. reads done as part of DML statements
+      //   to validate that the data that was served at the snapshot time is
+      //   unchanged at commit time.
+      // * At all other isolation levels, if `read_lock_mode` is the default
+      //   value, then pessimistic read lock is used.
       READ_LOCK_MODE_UNSPECIFIED = 0;
 
       // Pessimistic lock mode.
       //
       // Read locks are acquired immediately on read.
+      // Semantics described only applies to `SERIALIZABLE` isolation.
       PESSIMISTIC = 1;
 
       // Optimistic lock mode.
@@ -374,6 +385,7 @@ message TransactionOptions {
       // Locks for reads within the transaction are not acquired on read.
       // Instead the locks are acquired on a commit to validate that
       // read/queried data has not changed since the transaction started.
+      // Semantics described only applies to `SERIALIZABLE` isolation.
       OPTIMISTIC = 2;
     }
 
@@ -461,6 +473,38 @@ message TransactionOptions {
     bool return_read_timestamp = 6;
   }
 
+  // `IsolationLevel` is used when setting `isolation_level` for a transaction.
+  enum IsolationLevel {
+    // Default value.
+    //
+    // If the value is not specified, the `SERIALIZABLE` isolation level is
+    // used.
+    ISOLATION_LEVEL_UNSPECIFIED = 0;
+
+    // All transactions appear as if they executed in a serial order, even if
+    // some of the reads, writes, and other operations of distinct transactions
+    // actually occurred in parallel. Spanner assigns commit timestamps that
+    // reflect the order of committed transactions to implement this property.
+    // Spanner offers a stronger guarantee than serializability called external
+    // consistency. For further details, please refer to
+    // https://cloud.google.com/spanner/docs/true-time-external-consistency#serializability.
+    SERIALIZABLE = 1;
+
+    // All reads performed during the transaction observe a consistent snapshot
+    // of the database, and the transaction will only successfully commit in the
+    // absence of conflicts between its updates and any concurrent updates that
+    // have occurred since that snapshot. Consequently, in contrast to
+    // `SERIALIZABLE` transactions, only write-write conflicts are detected in
+    // snapshot transactions.
+    //
+    // This isolation level does not support Read-only and Partitioned DML
+    // transactions.
+    //
+    // When `REPEATABLE_READ` is specified on a read-write transaction, the
+    // locking semantics default to `OPTIMISTIC`.
+    REPEATABLE_READ = 2;
+  }
+
   // Required. The type of transaction.
   oneof mode {
     // Transaction may write.
@@ -500,6 +544,9 @@ message TransactionOptions {
   // partitioned-dml transactions, otherwise the API will return an
   // `INVALID_ARGUMENT` error.
   bool exclude_txn_from_change_streams = 5;
+
+  // Isolation level for the transaction.
+  IsolationLevel isolation_level = 6;
 }
 
 // A transaction.