diff --git a/metaflow/plugins/aws/aws_client.py b/metaflow/plugins/aws/aws_client.py
index 71479b52ce1..ff888b49234 100644
--- a/metaflow/plugins/aws/aws_client.py
+++ b/metaflow/plugins/aws/aws_client.py
@@ -35,6 +35,8 @@ def get_client(
                 "Could not import module 'boto3'. Install boto3 first."
             )
 
+        from metaflow.version import metaflow_version
+
         # Convert dictionary config to Config object if needed
         if "config" in client_params and not isinstance(
             client_params["config"], Config
@@ -49,6 +51,18 @@ def get_client(
             config.retries = S3_CLIENT_RETRY_CONFIG
             client_params["config"] = config
 
+        if module == "s3":
+            # Identify Metaflow to any S3-compatible endpoint, appending to (not
+            # replacing) any user agent the caller already configured.
+            config = client_params.get("config", Config())
+            ua = "metaflow/%s" % metaflow_version
+            existing_ua = config.user_agent_extra
+            if not existing_ua:
+                config.user_agent_extra = ua
+            elif ua not in existing_ua.split():
+                config.user_agent_extra = "%s %s" % (existing_ua, ua)
+            client_params["config"] = config
+
         if AWS_SANDBOX_ENABLED:
             # role is ignored in the sandbox
             global cached_aws_sandbox_creds