diff --git a/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStoragePath.java b/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStoragePath.java
index 92780d535846..32083da801b2 100644
--- a/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStoragePath.java
+++ b/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/CloudStoragePath.java
@@ -108,7 +108,10 @@ boolean seemsLikeADirectoryAndUsePseudoDirectories(Storage storage) {
             this.bucket(),
             Storage.BlobListOption.prefix(prefix),
             // we only look at the first result, so no need for a bigger page.
-            Storage.BlobListOption.pageSize(1));
+            Storage.BlobListOption.pageSize(1),
+            fileSystem.provider().getProject() == null
+                ? null
+                : Storage.BlobListOption.userProject(fileSystem.provider().getProject()));
     for (Blob b : list.getValues()) {
       // if this blob starts with our prefix and then a slash, then prefix is indeed a folder!
       if (b.getBlobId() == null) {
diff --git a/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/testing/FakeStorageRpc.java b/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/testing/FakeStorageRpc.java
index bee18dda5290..ee18735425f0 100644
--- a/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/testing/FakeStorageRpc.java
+++ b/google-cloud-clients/google-cloud-contrib/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/testing/FakeStorageRpc.java
@@ -145,6 +145,9 @@ public Tuple<String, Iterable<StorageObject>> list(String bucket, Map<Option, ?>
         case MAX_RESULTS:
           maxResults = (Long) e.getValue();
           break;
+        case USER_PROJECT:
+          // prevent unsupported operation
+          break;
         default:
           throw new UnsupportedOperationException("Unknown option: " + e.getKey());
       }