It works like this: 1) You port your number to GV. That has the effect of cancelling your carrier plan - you're no longer their customer. (Same as if you ported

It works like this: 1) You port your number to GV. That has the effect of cancelling your carrier plan - you're no longer their customer. (Same as if you ported from Carrier A to Carrier B.) You may have to pay early termination fees. 2) You then start over with your carrier (or a new one) - say "please give me service with a brand new number. Oh look, I already have a phone." 3) Once your cell phone has a number, you put that into GV as a forwarding number. Now the number that everyone already knows is your GV number, and you can keep your mobile number a secret if you like.