Something practical is happening in the switcher-deal lane: T-Mobile is still pitching Keep and Switch as a way to move carriers without eating the full remaining balance on a financed phone.
That can be useful if your phone is paid down enough to unlock, but it is not free money. The offer has carrier, proof, timing, and reimbursement rules that can change the math quickly if you port first and read later.
T-Mobile Keep and Switch: what the offer says
T-Mobile’s support page says Keep and Switch can reimburse a previous carrier’s remaining device payment balance up to $800 per line through a virtual prepaid Mastercard. The same page says the offer is capped at four lines per account.
The offer is built for people who are bringing their phone and number, not buying a subsidized phone first. T-Mobile says customers must activate a new voice line, bring or port the number to that line, and submit proof of eligible device financing.
What this means for you: treat the $800 figure as a ceiling, not a guaranteed check. Your actual reimbursement depends on the remaining eligible balance and whether your documentation matches T-Mobile’s rules.
The proof requirement is where shoppers get tripped up
T-Mobile’s switch page says customers must submit proof of balance and at least 90 days in good standing with the prior carrier and device within 30 days of port-in. It also says the prepaid card typically arrives within 15 days after rebate submission, and that the card expires in six months.
That sequence matters. If your old bill does not show the device balance clearly, or you miss the 30-day submission window, the reimbursement can become a customer-service problem instead of a savings move.
What to do: download the most recent bill and the device financing page before you port. Save a PDF copy, not just screenshots inside an app you may lose access to after canceling service.
Check your phone unlock before you port
T-Mobile’s switch page tells customers to make sure the phone is unlocked and ready for the T-Mobile network before bringing the number over. It also says customers with phones locked to another eligible carrier will have to pay off the phone and request an unlock from that carrier.
This is the part that can erase the headline savings for families. If you must pay off several phones first, you need enough cash on hand to float that balance while you wait for any reimbursement.
What this means for you: do not port the number until the old carrier confirms the phone is unlocked, compatible, and no longer tied to a payment lock.
Compare it with Verizon’s switcher discount
Verizon is also using switcher language around its Simplicity plan. Verizon’s switch page lists a $30 monthly line price after Auto Pay and Switcher Discount, plus taxes and fees. The fine print says the $10 monthly Auto Pay discount requires enrollment within 30 days, and the $15 monthly Switcher discount requires a smartphone line port-in or an uploaded mobile bill from an eligible carrier dated within the past 45 days.
Those are different kinds of incentives. T-Mobile’s Keep and Switch focuses on reimbursing a remaining device balance. Verizon’s switcher language focuses on lowering the monthly line price when the customer meets discount rules.
What to do: compare the first 12 months, not just the first bill. A device payoff reimbursement and a monthly plan discount solve different problems.
The SaveOnPhone read
- Best fit: you have a financed phone, an eligible prior carrier, clean documentation, and a phone that can be unlocked before the move.
- Biggest risk: paying off the old phone first and then missing a reimbursement rule after the number ports.
- Cash-flow check: a reimbursement card is not the same as never paying the balance. You may need to front the payoff.
- Plan check: the phone payoff only helps if the new monthly plan is still a good fit after taxes, fees, hotspot needs, and perks.
What to do this week
- Write down each phone’s remaining device balance and payoff date.
- Confirm your prior carrier appears in T-Mobile’s eligibility rules before starting the port.
- Download the bill and financing proof before canceling the old account.
- Ask the old carrier to unlock the phone and verify compatibility on T-Mobile’s network.
- Compare T-Mobile’s all-in monthly cost against Verizon’s switcher discount and your current bill.
Bottom line: Keep and Switch can be a strong escape hatch if your device balance is the thing keeping you stuck. Just do the paperwork in the right order. The deal is only worth chasing if the reimbursement clears and the new plan lowers your real monthly cost.