diff --git a/src/borg/helpers/progress.py b/src/borg/helpers/progress.py
index ed8e491a7..1968c3553 100644
--- a/src/borg/helpers/progress.py
+++ b/src/borg/helpers/progress.py
@@ -86,7 +86,7 @@ class ProgressIndicatorBase:
             finished=finished,
             time=time.time(),
         ))
-        print(json.dumps(kwargs), file=sys.stderr)
+        print(json.dumps(kwargs), file=sys.stderr, flush=True)
 
     def finish(self):
         if self.json: