diff --git a/changelog/fixed/tiptoeing-terrapin.md b/changelog/fixed/tiptoeing-terrapin.md
new file mode 100644
index 000000000..6d5bcc718
--- /dev/null
+++ b/changelog/fixed/tiptoeing-terrapin.md
@@ -0,0 +1 @@
+Send a request ID when terminating a standalone activity, so a retried `ActivityHandle.terminate()` call no longer fails after the first attempt already terminated the activity.
diff --git a/temporalio/client/_impl.py b/temporalio/client/_impl.py
index 3986f9e82..b8864c4e7 100644
--- a/temporalio/client/_impl.py
+++ b/temporalio/client/_impl.py
@@ -687,6 +687,7 @@ async def terminate_activity(self, input: TerminateActivityInput) -> None:
                 run_id=input.activity_run_id or "",
                 reason=input.reason or "",
                 identity=self._client.identity,
+                request_id=str(uuid.uuid4()),
             ),
             retry=True,
             metadata=input.rpc_metadata,
diff --git a/tests/test_activity.py b/tests/test_activity.py
index b3208d951..b17d587d8 100644
--- a/tests/test_activity.py
+++ b/tests/test_activity.py
@@ -112,6 +112,25 @@ async def test_start_activity_generates_request_id() -> None:
     assert requests[0].request_id != requests[1].request_id
 
 
+async def test_terminate_activity_generates_request_id() -> None:
+    terminate_activity_execution = mock.AsyncMock(
+        return_value=temporalio.api.workflowservice.v1.TerminateActivityExecutionResponse()
+    )
+    service_client = mock.MagicMock()
+    service_client.config.identity = "test-identity"
+    service_client.workflow_service.terminate_activity_execution = (
+        terminate_activity_execution
+    )
+    client = Client(service_client)
+
+    for activity_id in ("activity-id-1", "activity-id-2"):
+        await client.get_activity_handle(activity_id).terminate(reason="done")
+
+    requests = [call.args[0] for call in terminate_activity_execution.call_args_list]
+    assert all(uuid.UUID(request.request_id).version == 4 for request in requests)
+    assert requests[0].request_id != requests[1].request_id
+
+
 class TestDescribe:
     @pytest.fixture
     def task_queue(self):