diff --git a/xbout/region.py b/xbout/region.py
index 17bf6454..b6653824 100644
--- a/xbout/region.py
+++ b/xbout/region.py
@@ -1220,6 +1220,7 @@ def _create_regions_toroidal(ds):
     _check_connections(regions)
 
     ds = _set_attrs_on_all_vars(ds, "regions", regions)
+    ds.metadata["topology"] = topology
 
     return ds