Tello is a T/Mobile MVNO in the US which offers good support for Voice-over-Wifi, whereby voice and SMS can be sent using an Internet connection while overseas and not require expensive roaming minutes. We were successfully able to use VoWifi on our recent trip to Europe:
- SMS text messages arrived
- SMS messages sent were delivered
- incoming calls ring the phone
- outgoing calls work, and carried by usual US number as the callerID
The most important setting we needed to set was "Automatic data switching." My Tello plan includes no roaming minutes at all, I had installed a travel eSIM from Roamless.
