If you’re a postpaid customer on another network, T-Mobile will reimburse your early termination fee if you trade in your old smartphone and switch to their service. For prepaid customers, however, who pay the full cost of their smartphone and want to bring their old phone and number to T-Mobile, things get a little more complicated.
Owners of prepaid Sprint and Verizon phones, or smartphones on carriers like Virgin Mobile which use their networks, are out of luck. Phones designed to work with their networks aren’t compatible with T-Mobile. I just got my AT&T prepaid phone (a Lumia 520) switched over to T-Mobile’s $30 prepaid unlimited web plan with 100 minutes, though, and it’s working great!
Here’s what you’ll need to do it yourself:
An unlocked phone
Did you buy your phone from AT&T, instead of getting it unlocked from the manufacturer? Don’t fret! If you’ve paid for 6 months of service for your prepaid AT&T phone, you can go to AT&T’s website to have them unlock it for you.
There’s another site you can go to, to check on the status of your existing unlock request.
I think it only took them a few days in my case, but they probably won’t unlock it immediately at any rate. In the meantime, you need to stay subscribed to AT&T or at least not cancel your service with them, even if you don’t pay to refill it. You should also call AT&T to find out …
Your account number
If you want to port your existing number over to T-Mobile’s service, you need your AT&T prepaid account’s account number and PIN. As it turns out, AT&T’s My Prepaid Refill website doesn’t actually tell you this number, at least not anywhere I could see. I thought my phone number would work, since that’s what I use to sign in there, but it turns out that it doesn’t.
Maybe it’s in one of the email confirmations AT&T sends you when you order service with them. But the way I personally found out was to call AT&T’s customer service, and ask them what my account number was. The “contact us” link on My Prepaid Refill is broken right now, but att.com should have people you can talk to in order to at least point you in the right direction. (I had to go through several.)
A T-Mobile SIM card for prepaid phones
You’ll want to order this ahead of time, since if you don’t pick it up at the store you’ll need to wait for it to be mailed to you. T-Mobile sells them on their website, and occasionally has them for cheap but the normal price is just $10.
Even if T-Mobile’s website doesn’t list your phone as compatible, it may still work with it; my Lumia 520 wasn’t on their list, and it works fine. You’ll want to check the manufacturer’s website or the instruction manual to find out what kind of SIM you need to order, though, because there are three different sizes.