Vo-WiFi is Wifi Calling.

Voice over WiFi

If your phone is connected to a WiFi network and you wish to make or receive a call then this can be carried out seamlessly with the phone call travelling over the WiFi network prior to travelling over the Internet. It can also be used in areas of low or poor mobile connection. Throughout the London Underground there ae various WiFi stations that passengers can connect to and make calls using Vo-WiFi.

All 4 mobile operators support Vo-WiFi but not all virtual operator do currently. To get Vo-WiFi or WiFi calling, this needs to be set up on your phone, and potentially with the operator.

During aphone call, if you are moving about and loose the WiFi connection then the call wil;l transfer seamlessly to 4G (Vo-LTE) or vice versa.

One advantage for a business that has supported staff working from home and given a company mobile phone. These devices will work internally, inside the office and connected to the company WiFi without incurring cost of mobile calls. This means there is no need for an internal phone network for the company.