diff --git a/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_client.py b/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_client.py
index a3d9e0407d0..44057ae0af0 100644
--- a/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_client.py
+++ b/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_client.py
@@ -670,8 +670,8 @@ if __name__ == "__main__":
     parser.add_argument(
         "--enable_csm_observability",
         help="Whether to enable CSM Observability",
-        default=False,
-        action="store_true",
+        default="False",
+        type=bool_arg,
     )
     parser.add_argument(
         "--request_payload_size",
diff --git a/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_server.py b/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_server.py
index 0d7b73ed348..d2dd90a9b9c 100644
--- a/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_server.py
+++ b/src/python/grpcio_tests/tests_py3_only/interop/xds_interop_server.py
@@ -218,8 +218,8 @@ if __name__ == "__main__":
     parser.add_argument(
         "--enable_csm_observability",
         help="Whether to enable CSM Observability",
-        default=False,
-        action="store_true",
+        default="False",
+        type=bool_arg,
     )
     args = parser.parse_args()
     if args.verbose: