diff --git a/fireworks/core/firework.py b/fireworks/core/firework.py
index 8126b679d..7ab607751 100644
--- a/fireworks/core/firework.py
+++ b/fireworks/core/firework.py
@@ -15,7 +15,7 @@
 import pprint
 from collections import defaultdict
 from copy import deepcopy
-from datetime import UTC, datetime
+from datetime import datetime, timezone
 from typing import Any, Iterator, NoReturn, Sequence
 
 from monty.io import reverse_readline, zopen
@@ -579,7 +579,7 @@ def reservedtime_secs(self):
         """
         start = self.time_reserved
         if start:
-            end = self.time_start or datetime.now(tz=UTC)
+            end = self.time_start or datetime.now(tz=timezone.utc)
             return (end - start).total_seconds()
         return None
 
diff --git a/fireworks/core/rocket.py b/fireworks/core/rocket.py
index 0de71483e..34975398d 100644
--- a/fireworks/core/rocket.py
+++ b/fireworks/core/rocket.py
@@ -15,7 +15,7 @@
 import pdb
 import shutil
 import traceback
-from datetime import UTC, datetime
+from datetime import datetime, timezone
 from threading import Event, Thread, current_thread
 from typing import TYPE_CHECKING
 
@@ -51,7 +51,7 @@ def do_ping(launchpad: LaunchPad, launch_id: int) -> None:
         launchpad.ping_launch(launch_id)
     else:
         with open("FW_ping.json", "w") as f:
-            f.write(f'{{"ping_time": "{datetime.now(tz=UTC).isoformat()}"}}')
+            f.write(f'{{"ping_time": "{datetime.now(tz=timezone.utc).isoformat()}"}}')
 
 
 def ping_launch(launchpad: LaunchPad, launch_id: int, stop_event: Event, master_thread: Thread) -> None: