diff --git a/src/pretix/api/views/checkin.py b/src/pretix/api/views/checkin.py
index 01f0a447c1..185c7a6192 100644
--- a/src/pretix/api/views/checkin.py
+++ b/src/pretix/api/views/checkin.py
@@ -684,7 +684,7 @@ class CheckinListPositionViewSet(viewsets.ReadOnlyModelViewSet):
     serializer_class = CheckinListOrderPositionSerializer
     queryset = OrderPosition.all.none()
     filter_backends = (ExtendedBackend, RichOrderingFilter)
-    ordering = (F('attendee_name_cached').asc(nulls_last=True), 'positionid')
+    ordering = (F('attendee_name_cached').asc(nulls_last=True), 'pk')
     ordering_fields = (
         'order__code', 'order__datetime', 'positionid', 'attendee_name',
         'last_checked_in', 'order__email',