T-Mobile has quietly launched a new promotion called "Loyalty BYOD Dec 2025," offering select customers the opportunity to add a free line to their accounts this month. While details remain scarce, and the eligibility criteria are shrouded in mystery, this deal could provide a valuable benefit to qualifying customers.
Who Can Participate?
The unfortunate truth is that T-Mobile has not disclosed exactly who qualifies for this offer. The promotion is expected to go live later today, according to two independent sources—one of whom has a strong track record for accuracy on these sorts of leaks. As a segmented promotion, it seems likely that T-Mobile is targeting specific accounts in what appears to be a somewhat random selection process.
What we do know is that customers will need at least two active paid lines on their account to have a chance at receiving an additional free line. Beyond that, details like plan type, account age, or other factors remain unclear.
How to Check Your Eligibility
If you meet the basic requirement of maintaining two paid lines, you should keep an eye out for a promotional banner inside the T-Mobile T Life app. If no banner appears, you can politely contact T-Mobile customer support to inquire about the offer. While there’s no guarantee you’ll qualify, the potential payoff of a free line makes it well worth a quick ask.
Keep in mind that this promotion specifically requires bringing your own device (BYOD) to activate the new free line, so be prepared to use a compatible device that’s not purchased through T-Mobile.
Key Details and Limitations
This is not a traditional buy-one-get-one (BOGO) deal where you have to add a paid line first. Instead, it’s simpler and more generous, though it remains unpredictable and selective. The name of the promotion suggests it’s scheduled to run until roughly late December 2025, likely giving customers a window of about three weeks to act.
However, certain customer groups will probably be excluded, including those on Military, First Responder, and 55+ plans. Additionally, customers already carrying multiple free lines on their accounts may not be eligible, though the exact limit is unknown.
Is This a Return to T-Mobile’s "Un-carrier" Spirit?
While this deal may feel like a small step toward regaining the goodwill T-Mobile once enjoyed, it’s unlikely to fully restore the company’s original “Un-carrier” magic just yet. Recent years have seen a series of price increases, data breaches, and service issues that have frustrated many customers. For those who have stuck around, this promotion might be the first sign of more generous perks to come.
Historically, free lines were more frequently offered during the height of T-Mobile’s Un-carrier era, so perhaps this is the beginning of a trend toward such customer rewards again.
