Switching carriers
How to Switch to T-Mobile
What to check before you move, how to keep your number, and how to activate once you are on.
By M. Curtis McCoy · Last reviewed September 20, 2026 · How we make money
Switching to T-Mobile is three things in order: confirm your phone works on T-Mobile’s network, get your account number and transfer PIN from the carrier you are leaving, then start the transfer with T-Mobile. Do not cancel your old service first. The transfer closes it for you, and cancelling early releases your phone number.
T-Mobile runs on the T-Mobile network. T-Mobile owns and operates the network itself.
Before you start: three checks
1. Is your phone unlocked?
A phone bought on an instalment plan stays locked to that carrier until it is paid off and has been in service long enough to qualify. The carrier you are leaving has to unlock it — T-Mobile cannot. Ask them before you do anything else.
2. Will T-Mobile accept your handset?
Every US carrier shut down 3G in 2022. Calls now run over VoLTE, and carriers only allow it on handsets they have certified. A phone can show full bars and still fail to complete a call. Dial *#06# for your IMEI and run it through T-Mobile’s compatibility checker first.
3. eSIM or physical SIM?
Yes. T-Mobile pushed eSIM early and most current phones activate without a card. iPhone 14 and later sold in the United States have no SIM tray at all — they are eSIM only.
Switching to T-Mobile from your current carrier
The steps are the same everywhere. What changes is whether your phone needs checking first.
Switching to T-Mobile from Verizon
This is a network change: you are coming off Verizon and onto T-Mobile. Most phones sold in the US in the last few years carry the bands for all three, but that is not the same as being certified. Run your IMEI through T-Mobile’s compatibility checker before you pay for anything. Dial *#06# to get the IMEI.
Either way you need your account number and transfer PIN from Verizon first. Here is how to get them.
Switching to T-Mobile from AT&T
This is a network change: you are coming off AT&T and onto T-Mobile. Most phones sold in the US in the last few years carry the bands for all three, but that is not the same as being certified. Run your IMEI through T-Mobile’s compatibility checker before you pay for anything. Dial *#06# to get the IMEI.
Either way you need your account number and transfer PIN from AT&T first. Here is how to get them.
Switching to T-Mobile from T-Mobile
Your phone is already on T-Mobile’s network, so there is no compatibility question at all. The handset will work. What changes is the account it bills to and, if you are moving to a prepaid brand, where you sit in line when a tower is busy.
Either way you need your account number and transfer PIN from T-Mobile first. Here is how to get them.
On a different carrier? Find it in the database — there are port-out instructions for 230 of them.
How to activate your T-Mobile SIM or eSIM
- Have your account number, transfer PIN, and the billing name and address exactly as your old carrier has them. A mismatch here is the most common reason a transfer fails.
- Start the switch with T-Mobile and choose to keep your existing number.
- Install the eSIM or insert the physical SIM when T-Mobile tells you to — not before.
- Leave the old line active and the old phone powered on until the new one is working.
- Restart the phone once service appears. Carrier settings often do not apply until you do.
- Test a call and load a web page over cellular with Wi-Fi off.
If calls fail but data works, VoLTE has not been provisioned for your IMEI. Only T-Mobile can fix that, and on an uncertified handset they may not be able to. This is why the compatibility check comes first.
What it costs you to leave your current carrier
No US carrier is allowed to charge you a fee for transferring your number out. That is federal law, not a courtesy. What can still cost you:
- An unpaid device balance. If your phone is on an instalment plan, the remaining balance becomes due when the line closes, and the phone stays locked until it is paid.
- Promotional credits you were part way through. Trade-in and bill credits are usually spread over 24 or 36 months and stop the moment the line closes. You do not repay what you already received, but you lose the rest.
- A final partial bill. Postpaid carriers bill in arrears, so expect one more statement after the transfer.
Check the device balance and any remaining credits before you switch, not after. Those two numbers are the real cost of leaving, and neither one is a termination fee.
Is T-Mobile the right fit?
T-Mobile is the strongest of the three in dense urban areas and on mid-band 5G. It is weaker than Verizon in remote terrain. If you live in a city and travel internationally, it is usually the best of the three.
T-Mobile now owns Mint, Ultra and Metro too, so several of the cheaper options on this page are the same company.
First, get your account number and transfer PIN
You cannot start a transfer without them, and they come from the carrier you are leaving — not from T-Mobile. Pick yours:
Leaving T-MobileAccount number and transfer PIN
Leaving AT&TAccount number and transfer PIN
Every other carrierAll 230 US carriers and MVNOs
Some links on this page are affiliate links. We may earn a commission if you switch through them, at no cost to you. We recommend by network compatibility first, not by what pays most.
Common questions
Can I keep my phone number when I switch to T-Mobile?
Yes. Number portability is a legal right in the US. The only way to lose the number is to cancel the old line before the transfer completes.
How long does the switch take?
Most wireless-to-wireless transfers finish within a few hours. If yours is still pending after a business day, something you gave T-Mobile did not match your old carrier’s records — usually the account number or the billing address.
Will my phone work on T-Mobile?
T-Mobile runs on T-Mobile’s network. If you are already on T-Mobile, yes. Coming from another network, check the IMEI first — band support and VoLTE certification are different things, and it is the certification that decides whether calls connect.
Do I have to cancel my old plan?
No, and you should not. The transfer closes the old line for you. Cancelling first releases your number and you will probably lose it.
Will T-Mobile charge me to bring my number?
No. Neither carrier may charge a fee for the transfer itself. Device balances and lost promotional credits are separate, and they sit with the carrier you are leaving.
Best Cellular is a free reference site published by Assertive Holdings, LLC. We sell no wireless service and operate no stores. Some links on this page are affiliate links, which means we may earn a commission if you switch through them, at no cost to you. It does not change what we publish. Verified September 2026.