diff --git a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/datastore/DatastoreV1.java b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/datastore/DatastoreV1.java
index 042887994ec4..7e88de712b69 100644
--- a/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/datastore/DatastoreV1.java
+++ b/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/datastore/DatastoreV1.java
@@ -919,7 +919,8 @@ private RunQueryResponse runQueryWithRetries(RunQueryRequest request) throws Exc
                   options.getProjectId(), options.getNamespace()));
           baseLabels.put(MonitoringInfoConstants.Labels.DATASTORE_PROJECT, options.getProjectId());
           baseLabels.put(
-              MonitoringInfoConstants.Labels.DATASTORE_NAMESPACE, options.getNamespace());
+              MonitoringInfoConstants.Labels.DATASTORE_NAMESPACE,
+              String.valueOf(options.getNamespace()));
           ServiceCallMetric serviceCallMetric =
               new ServiceCallMetric(MonitoringInfoConstants.Urns.API_REQUEST_COUNT, baseLabels);
           try {