diff --git a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamCalcRel.java b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamCalcRel.java
index 044e75574391..6c8adc006df9 100644
--- a/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamCalcRel.java
+++ b/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamCalcRel.java
@@ -56,6 +56,8 @@
 import org.apache.beam.sdk.schemas.logicaltypes.FixedBytes;
 import org.apache.beam.sdk.schemas.logicaltypes.FixedPrecisionNumeric;
 import org.apache.beam.sdk.schemas.logicaltypes.FixedString;
+import org.apache.beam.sdk.schemas.logicaltypes.MicrosInstant;
+import org.apache.beam.sdk.schemas.logicaltypes.NanosInstant;
 import org.apache.beam.sdk.schemas.logicaltypes.PassThroughLogicalType;
 import org.apache.beam.sdk.schemas.logicaltypes.SqlTypes;
 import org.apache.beam.sdk.schemas.logicaltypes.VariableBytes;
@@ -416,6 +418,10 @@ static Object toBeamObject(Object value, FieldType fieldType, boolean verifyValu
         String identifier = logicalType.getIdentifier();
         if (TimeWithLocalTzType.IDENTIFIER.equals(identifier)) {
           return Instant.ofEpochMilli(((Number) value).longValue());
+        } else if (MicrosInstant.IDENTIFIER.equals(identifier)
+            || NanosInstant.IDENTIFIER.equals(identifier)) {
+          // Portable instant logical types: treat calcite numeric as epoch milliseconds.
+          return java.time.Instant.ofEpochMilli(((Number) value).longValue());
         } else if (SqlTypes.DATE.getIdentifier().equals(identifier)) {
           if (value instanceof Date) {
             value = SqlFunctions.toInt((Date) value);
@@ -574,6 +580,17 @@ private static Expression getBeamField(
             value = Expressions.call(expression, "getBytes", fieldName);
           } else if (TimeWithLocalTzType.IDENTIFIER.equals(identifier)) {
             value = Expressions.call(expression, "getDateTime", fieldName);
+          } else if (MicrosInstant.IDENTIFIER.equals(identifier)
+              || NanosInstant.IDENTIFIER.equals(identifier)) {
+            // Instant-like logical types: retrieve as Instant
+            value =
+                Expressions.convert_(
+                    Expressions.call(
+                        expression,
+                        "getLogicalTypeValue",
+                        fieldName,
+                        Expressions.constant(java.time.Instant.class)),
+                    java.time.Instant.class);
           } else if (SqlTypes.DATE.getIdentifier().equals(identifier)) {
             value =
                 Expressions.convert_(
@@ -661,6 +678,13 @@ private static Expression toCalciteValue(Expression value, FieldType fieldType)
           } else if (TimeWithLocalTzType.IDENTIFIER.equals(identifier)) {
             return nullOr(
                 value, Expressions.call(Expressions.convert_(value, DateTime.class), "getMillis"));
+          } else if (MicrosInstant.IDENTIFIER.equals(identifier)
+              || NanosInstant.IDENTIFIER.equals(identifier)) {
+            // Convert java.time.Instant to epoch milliseconds for Calcite
+            return nullOr(
+                value,
+                Expressions.call(
+                    Expressions.convert_(value, java.time.Instant.class), "toEpochMilli"));
           } else if (SqlTypes.DATE.getIdentifier().equals(identifier)) {
             return nullOr(
                 value,