Get these four things from your current carrier before you switch

Before you switch carriers, get four things from your current one: your account number, a transfer PIN, an unlocked phone, and your remaining device balance. Then start the number transfer while activating the new line, and don’t cancel the old one yourself.

Switching carriers is mostly waiting. The parts that go wrong are almost always things you were supposed to collect beforehand and didn’t, and by the time you notice you’re mid-port with two carriers holding half your number.

This is the checklist, in the order it matters. I haven’t run it on every carrier here; it’s assembled from what the carriers publish and what people who’ve done it report. The one switch I’ve done myself, Xfinity Mobile to US Mobile, will get its own page with real dates once I’ve written up the receipts.

1. Where do you find your account number?

Not your phone number. The account number, which on most carriers is nowhere near as visible as you’d expect and is sometimes different from the number printed on the bill.

Where it lives varies: the carrier’s app under account details, the top of a paper bill, or support chat if neither works. Get it written down before you start anything else.

2. How do you get a transfer PIN?

Each carrier’s exact steps, and how long its PIN lasts, are in the transfer PIN guide.

This is the one people don’t know exists. It’s a short code, separate from your account password, that authorises moving your number to another carrier. The new carrier asks for it at the moment you sign up.

Two things to know:

• It usually expires. Most carriers issue one valid for a few days. Get it when you’re ready to switch, not a month ahead.
• It’s not your account password or the last four of your SSN. Some carriers historically used those; the industry moved to explicit transfer PINs specifically to stop unauthorised ports.

Request it through the app or support chat. It’s routine and they’ll issue it.

3. Is your phone unlocked?

If you bought the phone from your carrier on a payment plan, it’s almost certainly locked to them until it’s paid off. A phone bought from a prepaid carrier can be locked even when it’s paid for: Cricket, and Verizon and AT&T’s prepaid phones, stay locked for a year of paid service. A locked phone will not take another carrier’s SIM or eSIM, and you’ll find this out at the worst possible moment.

Your phone’s settings usually show whether a carrier lock is on, though the wording varies by phone. The reliable move is to ask the carrier directly.

Two things that catch people:

• Each phone unlocks on its own terms. A family plan with four phones can have four different dates, depending on when each was bought and paid off.
• Paid off is not the same as unlocked. Verizon and Xfinity unlock automatically once a phone qualifies, and T-Mobile does for phones that support remote unlocking; AT&T, Spectrum and Cricket need a request. Seven carriers’ rules are side by side in the unlocking guide.

If you bought the phone unlocked from the manufacturer or a store, you can skip this. If you bought it outright from a carrier, check that carrier’s rules first.

4. What do you still owe on the phone?

Separate this from the service comparison, because they’re different decisions wearing the same number on your bill.

A monthly bill of $95 might be $55 of service and $40 of phone. Only the $55 is what you’re comparing against a $25 prepaid plan. And the remaining device balance comes due when you leave, whether or not the new carrier is cheaper.

Pull your last bill and split it: service, device, insurance, taxes. Then use the service line in the calculator.

In what order should you do it?

Once you have all four:

1. Sign up with the new carrier and start the port during activation. Not after. Carriers’ own porting instructions generally put it at activation, and doing it later is a common mistake: people activate a new temporary number, then try to bring their real number across later.
2. Enter the account number, the transfer PIN, and the billing ZIP exactly as the old carrier has them. A mismatch on any of the three stalls the port, and the error messages are rarely specific about which one.
3. Keep the old line active and wait. Minutes to a few hours is typical; a day is possible. Texts may stop briefly at the handoff.
4. Test properly before celebrating. Make a call, send a text to someone on a different network, and load a page on cellular with Wi-Fi off.
5. Let the port close the old account. Do not cancel it yourself. Porting terminates that line automatically, and cancelling first releases the number.
6. Watch the final bill. Prorated service plus any device balance. If you were bundled with home internet, check what the internet price becomes without the mobile line.

How long does a switch take?

If you’re on a prepaid plan you’ve already paid for the month, switch near the end of the cycle; that money doesn’t come back. If you’re postpaid you’ll get a prorated final bill either way, so timing matters less.

And if the new carrier offers a trial, read whether it needs a number ported in. If it does, you can test the network with a spare number rather than committing your real one.

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Assembled from carrier documentation and reported experience, September 2026. If your switch went sideways in a way this doesn’t cover, tell me and I’ll add it.