diff --git a/src/soundevent/io/aoef/sequence_annotation.py b/src/soundevent/io/aoef/sequence_annotation.py
index fbfb556..c07a657 100644
--- a/src/soundevent/io/aoef/sequence_annotation.py
+++ b/src/soundevent/io/aoef/sequence_annotation.py
@@ -83,5 +83,5 @@ def assemble_soundevent(
             created_by=self.user_adapter.from_id(obj.created_by)
             if obj.created_by is not None
             else None,
-            created_on=obj.created_on,
+            created_on=obj.created_on or datetime.datetime.now(),
         )
diff --git a/src/soundevent/io/aoef/sound_event_annotation.py b/src/soundevent/io/aoef/sound_event_annotation.py
index 2dee34b..e03f27b 100644
--- a/src/soundevent/io/aoef/sound_event_annotation.py
+++ b/src/soundevent/io/aoef/sound_event_annotation.py
@@ -80,5 +80,5 @@ def assemble_soundevent(
             created_by=self.user_adapter.from_id(obj.created_by)
             if obj.created_by is not None
             else None,
-            created_on=obj.created_on,
+            created_on=obj.created_on or datetime.datetime.now(),
         )