diff --git a/list-branch-pr b/list-branch-pr
index 00ebb6aa..2d38ac1f 100755
--- a/list-branch-pr
+++ b/list-branch-pr
@@ -268,7 +268,7 @@ def main(args):
         # sorting, so default to the empty string if so.
         for pull in sorted(prs, key=lambda pr: pr["waiting_since"] or ""):
             commit_timestr = pull["waiting_since"]
-            commit_time = datetime.fromisoformat(commit_timestr) \
+            commit_time = datetime.fromisoformat(commit_timestr.replace("Z", "+00:00")) \
                 if commit_timestr else datetime.now(timezone.utc)
             print(group, pull["number"], pull["sha"], pull["build_config"],
                   int(commit_time.timestamp()), sep="\t")