Wi-Fi Calling lets you talk, text, and use Visual Voicemail over an active Wi-Fi® connection. In the U.S., Wi-Fi Calling is used when a cellular signal is weak or unavailable. Outside the U.S., your phone will use a Wi-Fi network instead of a mobile network if both are available. (Wi-Fi Calling is restricted in some countries.)
Check phone compatibility
To find out if your device supports Wi-Fi Calling:
1. Tap Settings on your phone, then tap Cellular (Apple® devices) or Connection (Android® devices).
2. See if Wi-Fi Calling is listed.
Or, you can download a list of phones that support Wi-Fi Calling (PDF, 136KB).
Get more info on Wi-Fi Calling