diff --git a/main/src/main/java/org/mobilitydata/gtfsvalidator/validator/MissingShapesFileValidator.java b/main/src/main/java/org/mobilitydata/gtfsvalidator/validator/MissingShapesFileValidator.java
new file mode 100644
index 0000000000..d1595cb434
--- /dev/null
+++ b/main/src/main/java/org/mobilitydata/gtfsvalidator/validator/MissingShapesFileValidator.java
@@ -0,0 +1,75 @@
+package org.mobilitydata.gtfsvalidator.validator;
+
+import static org.mobilitydata.gtfsvalidator.notice.SeverityLevel.WARNING;
+
+import javax.inject.Inject;
+import org.mobilitydata.gtfsvalidator.annotation.GtfsValidationNotice;
+import org.mobilitydata.gtfsvalidator.annotation.GtfsValidationNotice.FileRefs;
+import org.mobilitydata.gtfsvalidator.annotation.GtfsValidator;
+import org.mobilitydata.gtfsvalidator.notice.MissingRecommendedFileNotice;
+import org.mobilitydata.gtfsvalidator.notice.NoticeContainer;
+import org.mobilitydata.gtfsvalidator.notice.ValidationNotice;
+import org.mobilitydata.gtfsvalidator.table.GtfsLocationGroupsTableContainer;
+import org.mobilitydata.gtfsvalidator.table.GtfsShapeTableContainer;
+import org.mobilitydata.gtfsvalidator.table.GtfsStopTime;
+import org.mobilitydata.gtfsvalidator.table.GtfsStopTimeSchema;
+import org.mobilitydata.gtfsvalidator.table.GtfsStopTimeTableContainer;
+import org.mobilitydata.gtfsvalidator.table.GtfsTripSchema;
+
+/**
+ * Validates that the feed has either a `shapes.txt` file, or uses zone-based DRT or fixed-stops
+ * DRT.
+ *
+ * <p>Generated notice: {@link MissingRecommendedFileNotice}.
+ */
+@GtfsValidator
+public class MissingShapesFileValidator extends FileValidator {
+  private final GtfsShapeTableContainer shapeTable;
+  private final GtfsStopTimeTableContainer stopTimeTable;
+  private final GtfsLocationGroupsTableContainer locationGroupsTable;
+
+  @Inject
+  MissingShapesFileValidator(
+      GtfsShapeTableContainer shapeTable,
+      GtfsStopTimeTableContainer stopTimeTable,
+      GtfsLocationGroupsTableContainer locationGroupsTable) {
+    this.shapeTable = shapeTable;
+    this.stopTimeTable = stopTimeTable;
+    this.locationGroupsTable = locationGroupsTable;
+  }
+
+  @Override
+  public void validate(NoticeContainer noticeContainer) {
+    Boolean missingShapes = shapeTable.isMissingFile();
+    Boolean hasLocationId = stopTimeTable.hasColumn("location_id");
+    Boolean hasLocationGroupId = stopTimeTable.hasColumn("location_group_id");
+    Boolean hasLocationGroupsRecord =
+          !locationGroupsTable.isMissingFile() && locationGroupsTable.entityCount() > 0;
+    // Detect DRT usage from the data, not just from column presence.
+    boolean hasLocationIdInData = false;
+    boolean hasLocationGroupIdInData = false;
+    for (GtfsStopTime stopTime : stopTimeTable.getEntities()) {
+      if (stopTime.hasLocationId()) {
+        hasLocationIdInData = true;
+      }
+      if (stopTime.hasLocationGroupId()) {
+        hasLocationGroupIdInData = true;
+      }
+      if (hasLocationIdInData && hasLocationGroupIdInData) {
+        break;
+      }
+    }
+
+    // Do we not have: a shapes.txt file and not have a location_id (required for Zone-Based DRT),
+    // and also not have a record in location_groups.txt and not have a trip in stop_times.txt that
+    // references location_group_id (required for Fixed-Stop DRT)?
+    if (missingShapes && !hasLocationId && !hasLocationGroupsRecord && !hasLocationGroupId) {
+      for (GtfsStopTime stopTime : stopTimeTable.getEntities()) {
+        noticeContainer.addValidationNotice(
+            new MissingRecommendedFileNotice("shapes.txt"));
+        // This is a feed-level warning; emit it at most once.
+        break;
+      }
+    }
+  }
+}
diff --git a/main/src/test/java/org/mobilitydata/gtfsvalidator/validator/MissingShapesFileValidatorTest.java b/main/src/test/java/org/mobilitydata/gtfsvalidator/validator/MissingShapesFileValidatorTest.java
new file mode 100644
index 0000000000..dd4f0d812b
--- /dev/null
+++ b/main/src/test/java/org/mobilitydata/gtfsvalidator/validator/MissingShapesFileValidatorTest.java
@@ -0,0 +1,121 @@
+package org.mobilitydata.gtfsvalidator.validator;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Test;
+import org.mobilitydata.gtfsvalidator.notice.MissingRecommendedFileNotice;
+import org.mobilitydata.gtfsvalidator.notice.NoticeContainer;
+import org.mobilitydata.gtfsvalidator.notice.ValidationNotice;
+import org.mobilitydata.gtfsvalidator.table.GtfsLocationGroups;
+import org.mobilitydata.gtfsvalidator.table.GtfsLocationGroupsTableContainer;
+import org.mobilitydata.gtfsvalidator.table.GtfsShape;
+import org.mobilitydata.gtfsvalidator.table.GtfsShapeTableContainer;
+import org.mobilitydata.gtfsvalidator.table.GtfsStopTime;
+import org.mobilitydata.gtfsvalidator.table.GtfsStopTimeTableContainer;
+import org.mobilitydata.gtfsvalidator.table.TableStatus;
+
+public class MissingShapesFileValidatorTest {
+
+  private static List<GtfsShape> createShapeTable(int rows) {
+    ArrayList<GtfsShape> shapes = new ArrayList<>();
+    for (int i = 0; i < rows; i++) {
+      shapes.add(new GtfsShape.Builder().setCsvRowNumber(i + 1).setShapeId("s" + i).build());
+    }
+    return shapes;
+  }
+
+  private static List<GtfsStopTime> createStopTimesTable(
+      int rows, String locationGroupId, String locationId) {
+    ArrayList<GtfsStopTime> stopTimes = new ArrayList<>();
+    for (int i = 0; i < rows; i++) {
+      stopTimes.add(
+          new GtfsStopTime.Builder()
+              .setCsvRowNumber(i + 1)
+              .setLocationGroupId(locationGroupId)
+              .setLocationId(locationId)
+              .setTripId(locationGroupId)
+              .setStopSequence(i + 1)
+              .build());
+    }
+    return stopTimes;
+  }
+
+  private static List<GtfsLocationGroups> createLocationGroupsTable(
+      int rows, String groupId, String groupName) {
+    ArrayList<GtfsLocationGroups> locationGroups = new ArrayList<>();
+    for (int i = 0; i < rows; i++) {
+      locationGroups.add(
+          new GtfsLocationGroups.Builder()
+              .setCsvRowNumber(i + 1)
+              .setLocationGroupId(groupId)
+              .setLocationGroupName(groupName)
+              .build());
+    }
+    return locationGroups;
+  }
+
+  @Test
+  public void testShapesFileAndFixedDrtPresent() {
+    List<ValidationNotice> notices =
+        generateNotices(
+            createShapeTable(1),
+            GtfsShapeTableContainer.forStatus(null),
+            createStopTimesTable(1, "a", null),
+            createLocationGroupsTable(1, "b", "testgroup"));
+    boolean found =
+        notices.stream()
+            .anyMatch(
+                notice ->
+                    notice instanceof MissingRecommendedFileNotice);
+    assertThat(found).isFalse();
+  }
+
+  @Test
+  public void testShapesFileAndZoneBasedDrtPresent() {
+    List<ValidationNotice> notices =
+        generateNotices(
+            createShapeTable(1),
+            GtfsShapeTableContainer.forStatus(null),
+            createStopTimesTable(1, null, "c"),
+            createLocationGroupsTable(1, "d", "t3stgroup"));
+    boolean found =
+        notices.stream()
+            .anyMatch(
+                notice ->
+                    notice instanceof MissingRecommendedFileNotice);
+    assertThat(found).isFalse();
+  }
+
+  @Test
+  public void testNoShapesFileAndNoDrtPresent() {
+    List<ValidationNotice> notices =
+        generateNotices(
+            createShapeTable(0),
+            GtfsShapeTableContainer.forStatus(TableStatus.MISSING_FILE),
+            createStopTimesTable(1, null, null),
+            createLocationGroupsTable(0, null, null));
+    long missingRecommendedFileNoticesCount =
+        notices.stream()
+            .filter(
+                notice ->
+                    notice instanceof MissingRecommendedFileNotice)
+            .count();
+    assertThat(missingRecommendedFileNoticesCount).isAtLeast(1);
+  }
+
+  private static List<ValidationNotice> generateNotices(
+      List<GtfsShape> shapes,
+      GtfsShapeTableContainer shapeContainer,
+      List<GtfsStopTime> stopTimes,
+      List<GtfsLocationGroups> locationGroups) {
+    NoticeContainer noticeContainer = new NoticeContainer();
+    new MissingShapesFileValidator(
+            GtfsShapeTableContainer.forEntities(shapes, noticeContainer),
+            GtfsStopTimeTableContainer.forEntities(stopTimes, noticeContainer),
+            GtfsLocationGroupsTableContainer.forEntities(locationGroups, noticeContainer))
+        .validate(noticeContainer);
+    return noticeContainer.getValidationNotices();
+  }
+}