diff --git a/src/aviary/env.py b/src/aviary/env.py
index f018afc2..38d90362 100644
--- a/src/aviary/env.py
+++ b/src/aviary/env.py
@@ -234,7 +234,7 @@ def export_frame(self) -> Frame:
         Read Field descriptions in Frame for more information.
         """
 
-    def close(self) -> None:
+    async def close(self) -> None:
         """
         Shutdown the environment.