diff --git a/xarray/coding/times.py b/xarray/coding/times.py
index 3e862e48e1f..3319720e26f 100644
--- a/xarray/coding/times.py
+++ b/xarray/coding/times.py
@@ -5,7 +5,7 @@
 from collections.abc import Callable, Hashable
 from datetime import datetime, timedelta
 from functools import partial
-from typing import TYPE_CHECKING, Optional, Union, cast
+from typing import TYPE_CHECKING, Union, cast
 
 import numpy as np
 import pandas as pd