Joe Maring / Android Authority TL;DR T-Mobile is offering some customers a free line as a limited-time promotion — though taxes, fees, and device connection charges apply. Users who accept the free line will have to Bring Your Own Device (BYOD) and note that promotional limitations will apply to that free line. Reddit users suggest verifying eligibility carefully through support channels and checking billing statements before activating new SIMs. T-Mobile does have some great plans and offers, but the carrier also hiked prices on its legacy plans earlier in the year. To soften the blow, the company rolled out a targeted promotion giving some users a free voice line. If you missed out on the offer back then, T-Mobile is now offering some users a free line, so it’s worth checking if you are eligible. There are also some catches that you should keep in mind before accepting the free line. Don’t want to miss the best from Android Authority? Set us as a favorite source in Google Discover to support us and make sure you never miss our latest exclusive reports, expert analysis, and much more. You can also set us as a preferred source in Google Search — find out more here. Several Reddit users (1, 2, 3, 4) report receiving an email or text from T-Mobile informing them that they are eligible to add a free line to their account. The email notes that this is a limited-time offer for family plan accounts. If the user accepts the offer, they will have to pay a $10 device connection charge, and pay taxes and fees on the line. So, while the line is free, you will incur some processing and regulatory costs. The users receiving this line are spread across several plans. According to reports, some users on ONE, Go5G, Go5G Plus, and even Unlimited Freedom (a legacy Sprint plan) have received the offer, but many others on the same plans have not yet. It does seem that if you already have two free lines, or you added a free line earlier in the year, you are unlikely to get this offer, but you can still try your luck. If you’ve cancelled lines in the past 90 days, you may need to reactivate them first to become eligible for this offer. Some users mentioned that price lock plans are not eligible, but one Reddit user on Magenta Max with six free lines was initially turned away from the app chat. Still, a customer service representative on the phone confirmed eligibility and added the free line, so your mileage may vary. If you do get it, let us know in the comments below, and do read till the end to learn how to verify your free line. There is some fine print that you should keep in mind before you accept the offer. Redditors mention that the free line that you take will never qualify for a free phone, an upgrade, or other promo. You will need to BYOD (Bring Your Own Device), and you will not be able to finance any device on the line for its lifetime. And if you were wondering, no, you cannot replace an existing paid line with this new free line. If you cancel any paid lines within a year after accepting this offer, you will be charged for the new “free” line. You can cancel a paid line after a year, though, so it may be worth accepting the free line now and taking action on the paid line a year later (you were going to pay for it anyway), presuming you can stomach the taxes on the free line until then. How to check if you qualify for T-Mobile’s free line promo To see if you qualify for the free line, you can message customer service and politely ask if you are eligible for the offer. You can also go to your local T-Mobile store and have the representative look at the segments section on your plan to see if there is a September 2025 BYOD verified status on there, as per this Reddit user. How to verify that the free line you accepted is indeed free If you are trying your luck with representatives, it is important to verify that the line you received is indeed free, as representatives have been mistaken about free line promos in the past. Reddit user stuffeh mentions that you can protect yourself by requesting the line be sent to you on a SIM card. When you receive the card, don’t put it into a phone immediately, but check the app or website to see if the line has been added to your account. Then, wait until your next bill is generated to see if the new line is listed there with the correct promo. If you see the free line and its promo discount on your next bill, congrats. You have a new free line, and you can use the SIM or convert it into an eSIM as needed. However, if the free line is not listed on the bill, you should contact customer service and inquire further. If it does turn out that the first representative was mistaken, you can push ahead to “No install the line” and be refunded (since the line has not been connected to the network, it will not count as a cancellation). Follow