diff --git a/swh/model/model.py b/swh/model/model.py
--- a/swh/model/model.py
+++ b/swh/model/model.py
@@ -257,6 +257,23 @@
     def from_datetime(cls, dt: datetime.datetime):
         return cls.from_dict(dt)
 
+    def to_datetime(self) -> datetime.datetime:
+        """Convert to a datetime (with a timezone set to the recorded fixed UTC offset)
+
+        Beware that this conversion can be lossy: the negative_utc flag is not
+        taken into consideration (since it cannot be represented in a
+        datetime). Also note that it may fail due to type overflow.
+
+        """
+        timestamp = datetime.datetime.fromtimestamp(
+            self.timestamp.seconds,
+            datetime.timezone(datetime.timedelta(minutes=self.offset)),
+        )
+        timestamp = timestamp.replace(microsecond=self.timestamp.microseconds)
+        if self.timestamp.seconds < 0 and self.timestamp.microseconds:
+            timestamp -= datetime.timedelta(seconds=1)
+        return timestamp
+
     @classmethod
     def from_iso8601(cls, s):
         """Builds a TimestampWithTimezone from an ISO8601-formatted string.
diff --git a/swh/model/tests/test_model.py b/swh/model/tests/test_model.py
--- a/swh/model/tests/test_model.py
+++ b/swh/model/tests/test_model.py
@@ -329,6 +329,29 @@
     )
 
 
+tzs = [
+    datetime.timezone(datetime.timedelta(minutes=+60)),
+    datetime.timezone.utc,
+    datetime.timezone(datetime.timedelta(hours=-1)),
+]
+dates = [
+    datetime.datetime(2020, 2, 27, 14, 39, 19),
+    datetime.datetime(2120, 12, 31, 23, 59, 59),
+    datetime.datetime(1610, 5, 14, 15, 43, 0),
+]
+
+
+@pytest.mark.parametrize("date", dates)
+@pytest.mark.parametrize("tz", tzs)
+@pytest.mark.parametrize("microsecond", [0, 1, 10, 100, 1000, 999999])
+def test_timestampwithtimezone_to_datetime(date, tz, microsecond):
+    date = date.replace(tzinfo=tz, microsecond=microsecond)
+    tstz = TimestampWithTimezone.from_datetime(date)
+
+    assert tstz.to_datetime() == date
+    assert tstz.to_datetime().utcoffset() == date.utcoffset()
+
+
 def test_person_from_fullname():
     """The author should have name, email and fullname filled.