diff --git a/src/pretix/api/serializers/event.py b/src/pretix/api/serializers/event.py
index 609466042e..38965fefd8 100644
--- a/src/pretix/api/serializers/event.py
+++ b/src/pretix/api/serializers/event.py
@@ -972,9 +972,19 @@ class ItemMetaPropertiesSerializer(I18nAwareModelSerializer):
 
 
 class SeatSerializer(I18nAwareModelSerializer):
+    has_order = serializers.BooleanField()
+    has_cart = serializers.BooleanField()
+    has_voucher = serializers.BooleanField()
+
     class Meta:
         model = Seat
-        read_only_fields = ('id', 'subevent', 'zone_name', 'row_name', 'row_label',
-                  'seat_number', 'seat_label', 'seat_guid', 'product', 'sorting_rank', 'x', 'y',)
-        fields = ('id', 'subevent', 'zone_name', 'row_name', 'row_label',
-                  'seat_number', 'seat_label', 'seat_guid', 'product', 'blocked', 'sorting_rank', 'x', 'y',)
+        read_only_fields = (
+            'id', 'subevent', 'zone_name', 'row_name', 'row_label',
+            'seat_number', 'seat_label', 'seat_guid', 'product', 'sorting_rank', 'x', 'y',
+            'has_order', 'has_cart', 'has_voucher',
+        )
+        fields = (
+            'id', 'subevent', 'zone_name', 'row_name', 'row_label',
+            'seat_number', 'seat_label', 'seat_guid', 'product', 'blocked', 'sorting_rank', 'x', 'y',
+            'has_order', 'has_cart', 'has_voucher',
+        )
diff --git a/src/pretix/api/views/event.py b/src/pretix/api/views/event.py
index b28c339bf8..dbbb27aa9f 100644
--- a/src/pretix/api/views/event.py
+++ b/src/pretix/api/views/event.py
@@ -674,10 +674,16 @@ class SeatViewSet(ConditionalListView, viewsets.ModelViewSet):
     queryset = Seat.objects.none()
     write_permission = 'can_change_event_settings'
     filter_backends = [DjangoFilterBackend]
-    filterset_fields = ['zone_name', 'row_name', 'row_label', 'seat_number', 'seat_label', 'seat_guid', 'blocked']
+    filterset_fields = ['subevent',
+                        'zone_name', 'row_name', 'row_label', 'seat_number', 'seat_label',
+                        'seat_guid', 'blocked',]
 
     def get_queryset(self):
-        return self.request.event.seats.all()
+        if self.request.event.has_subevents:
+            subevent = self.request.event.subevents.get(pk=self.request.GET.get('subevent'))
+            return Seat.annotated(event_id=self.request.event.id, subevent=subevent, qs=subevent.seats.all())
+        else:
+            return Seat.annotated(event_id=self.request.event.id, subevent=None, qs=self.request.event.seats.all())
 
     def perform_update(self, serializer):
         super().perform_update(serializer)