diff --git a/can/io/blf.py b/can/io/blf.py
index 64649ebaa..7d944a846 100644
--- a/can/io/blf.py
+++ b/can/io/blf.py
@@ -103,7 +103,7 @@ def timestamp_to_systemtime(timestamp: float) -> TSystemTime:
     if timestamp is None or timestamp < 631152000:
         # Probably not a Unix timestamp
         return 0, 0, 0, 0, 0, 0, 0, 0
-    t = datetime.datetime.fromtimestamp(round(timestamp, 3))
+    t = datetime.datetime.fromtimestamp(round(timestamp, 3), tz=datetime.timezone.utc)
     return (
         t.year,
         t.month,
@@ -126,6 +126,7 @@ def systemtime_to_timestamp(systemtime: TSystemTime) -> float:
             systemtime[5],
             systemtime[6],
             systemtime[7] * 1000,
+            tzinfo=datetime.timezone.utc,
         )
         return t.timestamp()
     except ValueError:
diff --git a/test/logformats_test.py b/test/logformats_test.py
index ef446e5d2..a2fd0fe09 100644
--- a/test/logformats_test.py
+++ b/test/logformats_test.py
@@ -791,7 +791,7 @@ def test_timestamp_to_systemtime(self):
 
     def test_issue_1905(self):
         expected = can.Message(
-            timestamp=1735650583.491113,
+            timestamp=1735654183.491113,
             channel=6,
             arbitration_id=0x6A9,
             is_extended_id=False,