diff --git a/data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/source/opensearch/worker/OpenSearchIndexPartitionCreationSupplier.java b/data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/source/opensearch/worker/OpenSearchIndexPartitionCreationSupplier.java
index 247a26b543..27ef37f6de 100644
--- a/data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/source/opensearch/worker/OpenSearchIndexPartitionCreationSupplier.java
+++ b/data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/source/opensearch/worker/OpenSearchIndexPartitionCreationSupplier.java
@@ -18,6 +18,7 @@
 import org.opensearch.dataprepper.plugins.source.opensearch.worker.client.ClusterClientFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import static org.opensearch.dataprepper.logging.DataPrepperMarkers.NOISY;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -26,7 +27,6 @@
 import java.util.Objects;
 import java.util.function.Function;
 import java.util.regex.Matcher;
-import java.util.stream.Collectors;
 
 public class OpenSearchIndexPartitionCreationSupplier implements Function<Map<String, Object>, List<PartitionIdentifier>> {
 
@@ -82,10 +82,18 @@ private List<PartitionIdentifier> applyForOpenSearchClient(final Map<String, Obj
 
         LOG.debug("Found {} indices", indicesResponse.valueBody().size());
 
-        return indicesResponse.valueBody().stream()
-                .filter(osIndicesRecord -> shouldIndexBeProcessed(osIndicesRecord.index()))
-                .map(indexRecord -> PartitionIdentifier.builder().withPartitionKey(indexRecord.index()).build())
-                .collect(Collectors.toList());
+        final List<PartitionIdentifier> partitions = new java.util.ArrayList<>();
+        int matchCount = 0;
+        for (final var esIndicesRecord : indicesResponse.valueBody()) {
+            if (shouldIndexBeProcessed(esIndicesRecord.index())) {
+                partitions.add(PartitionIdentifier.builder().withPartitionKey(esIndicesRecord.index()).build());
+                matchCount++;
+            }
+        }
+        if (matchCount == 0) {
+            LOG.warn(NOISY, "No indices matched the configured regex patterns after applying include/exclude filters");
+        }
+        return partitions;
     }
 
     private List<PartitionIdentifier> applyForElasticSearchClient(final Map<String, Object> globalStateMap) {
@@ -99,10 +107,18 @@ private List<PartitionIdentifier> applyForElasticSearchClient(final Map<String,
 
         LOG.debug("Found {} indices", indicesResponse.valueBody().size());
 
-        return indicesResponse.valueBody().stream()
-                .filter(esIndicesRecord -> shouldIndexBeProcessed(esIndicesRecord.index()))
-                .map(indexRecord -> PartitionIdentifier.builder().withPartitionKey(indexRecord.index()).build())
-                .collect(Collectors.toList());
+        final List<PartitionIdentifier> partitions = new java.util.ArrayList<>();
+        int matchCount = 0;
+        for (final var esIndicesRecord : indicesResponse.valueBody()) {
+            if (shouldIndexBeProcessed(esIndicesRecord.index())) {
+                partitions.add(PartitionIdentifier.builder().withPartitionKey(esIndicesRecord.index()).build());
+                matchCount++;
+            }
+        }
+        if (matchCount == 0) {
+            LOG.warn(NOISY, "No indices matched the configured regex patterns after applying include/exclude filters");
+        }
+        return partitions;
     }
 
     private boolean shouldIndexBeProcessed(final String indexName) {