diff --git a/modal/sandbox.py b/modal/sandbox.py
index e1775370e..a2a3ae178 100644
--- a/modal/sandbox.py
+++ b/modal/sandbox.py
@@ -132,7 +132,9 @@ async def _load(self: _Sandbox, resolver: Resolver, _existing_object_id: Optiona
             )
 
             # Note - `resolver.app_id` will be `None` for app-less sandboxes
-            create_req = api_pb2.SandboxCreateRequest(app_id=resolver.app_id, definition=definition)
+            create_req = api_pb2.SandboxCreateRequest(
+                app_id=resolver.app_id, definition=definition, environment_name=resolver.environment_name
+            )
             create_resp = await retry_transient_errors(resolver.client.stub.SandboxCreate, create_req)
 
             sandbox_id = create_resp.sandbox_id
diff --git a/modal_proto/api.proto b/modal_proto/api.proto
index ef7de5eac..ebb70d3de 100644
--- a/modal_proto/api.proto
+++ b/modal_proto/api.proto
@@ -1782,6 +1782,7 @@ message Sandbox {
 message SandboxCreateRequest {
   string app_id = 1 [ (modal.options.audit_target_attr) = true ];
   Sandbox definition = 2;
+  string environment_name = 3;
 }
 
 message SandboxCreateResponse {