Porting is the transfer of a phone number between two telephone service providers on behalf of an end-user. The process involves providing the right documentation to prove ownership of the number as well as coordination between the existing provider and the new provider with regard to the number's porting date.
When a port request is submitted to Twilio, we will port both Voice and SMS by default.
If you wish to leave Voice capabilities with the existing provider and only use Twilio for SMS, please read more about our Hosted SMS product (developer preview) instead.