A voice over WLAN diagnostic system. In particular implementations, a method includes simulating, in response to a triggering event, Voice over Internet Protocol (VoIP) communications with a remote diagnostics engine; gathering metric data characterizing one or more aspects of the simulated VoIP communications; and periodically transmitting diagnostic packets including the metric data to the remote diagnostics engine; wherein the simulating VoIP communications comprises transmitting diagnostic protocol packets that simulate VoIP communications to the remote diagnostic engine; and intercepting diagnostic protocol packets received from the diagnostics engine.