diff --git a/glean-core/ios/Glean/Net/PingUploader.swift b/glean-core/ios/Glean/Net/PingUploader.swift
index 5d07c5fed1..72eb71aabd 100644
--- a/glean-core/ios/Glean/Net/PingUploader.swift
+++ b/glean-core/ios/Glean/Net/PingUploader.swift
@@ -15,7 +15,7 @@ public protocol PingUploader {
      */
     func upload(
         request: CapablePingUploadRequest,
-        callback: @escaping (UploadResult) -> Void
+        callback: @escaping @Sendable (UploadResult) -> Void
     )
 }