diff --git a/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilder.java b/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilder.java
index b81d228d3e1b..8342ef46075f 100644
--- a/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilder.java
+++ b/mobile/android/base/java/org/mozilla/gecko/telemetry/pingbuilders/TelemetrySyncPingBuilder.java
@@ -141,6 +141,7 @@ public class TelemetrySyncPingBuilder extends TelemetryLocalPingBuilder {
 
     @Override
     public TelemetryLocalPing build() {
+        payload.put("when", System.currentTimeMillis());
         return new TelemetryLocalPing(payload, docID);
     }