All customers will have WiFi calling support. This may seem silly with an unlimited voice plan, but WiFi calling can allow you to make WiFi calls for areas that cellular phone service is non-existent, or hard to come by. Another option is to use WiFi calling if you traveled outside of the country. You can connect to your hotel’s Wifi Network, and make calls back to the US as if you were calling from within the US. You will want to make sure that you are connected to the WiFi network first.