While you’re abroad
Unfortunately, WiFi Calling doesn't work while you're abroad. But you can still use it to call international or premium rate numbers from the UK.
You can use WiFi Calling in public hotspots if the hotspot provider allows it. Make sure you've signed in securely, if not, you'll get a message asking you to. If WiFi Calling isn’t allowed on the hotspot network, the service won't work.
Your call quality will be at its best at 2Mb per second and can be impacted by slower connection speeds, so it’s best to check your speed using a speed test app. Try an app like Ookla, which can be downloaded via the app store on your device or by going to their website. Some internet providers also have speed tests on their website.