diff --git a/app/main/views/returned_letters.py b/app/main/views/returned_letters.py
index 6d6b24d12..09f3db4ab 100644
--- a/app/main/views/returned_letters.py
+++ b/app/main/views/returned_letters.py
@@ -17,7 +17,7 @@ def returned_letter_summary(service_id):
     )
 
 
-@main.route("/services/<uuid:service_id>/returned-letters-csv/<simple_date:reported_at>", methods=["GET"])
+@main.route("/services/<uuid:service_id>/returned-letters/<simple_date:reported_at>.csv", methods=["GET"])
 @user_has_permissions('view_activity')
 def returned_letters_report(service_id, reported_at):
     returned_letters = service_api_client.get_returned_letters(service_id, reported_at)