T-Mobile resurrects free line promo, with catches

T-Mobile has brought back its once-ubiquitous “free line” promotion and once again, it is not exactly what it seems. The offer is limited, largely for multi-line accounts only, and it’s loaded with fine print around taxes, fees, and device eligibility. If you’re thinking of taking the plunge, here’s what has changed and what hasn’t — and how to avoid a nasty surprise for that first bill.

What’s actually free with T-Mobile’s revived promotion

The carrier will temporarily waive the monthly service charge for an added voice line under certain accounts. That “free” line usually still prompts a one-time device connection fee of $10 or so, and includes ongoing taxes and regulatory fees. Those add-ons are nothing to sniff at; wireless taxes and fees usually account for around a quarter of an average phone bill in many states, according to the Tax Foundation, so budgeting even a couple dollars a month for that promo line makes sense even if the base rate is zero.

This wave seems to focus on family plans and legacy tiers. Eligibility has appeared on ONE, Magenta/Magenta Max, Go5G/Go5G Plus, and even old Sprint plans such as Unlimited Freedom, according to reports. But it’s far from universal. Two lines on the same plan could experience different results; and customers who obtained free lines in the past are not eligible.

Eligibility remains murky and varies by plan and account

T-Mobile is letting some customers know by text or email, but you don’t need a notification to ask. Frontline reps can look at your account’s promo segments and verify if a free-line SOC (the internal promo code) is there. Deferrals for customer-requested cancellations in the last 90 days. Customers with two active free lines are frequently denied, though it seems an account can be reactivated and you would then qualify.

There are also mixed results on “price lock” or legacy price-protection plans. App chat agents will occasionally say no; phone support reps or in-store diehards will occasionally find a way. In other words: results may vary, and commitment counts.

BYOD only, with significant limitations on device promos

The caveat, of course, is that the free line is typically BYOD (Bring Your Own Device).

You won’t be able to finance a phone on that line, and you’re unlikely to qualify for handset promos, upgrades, or bill credits tied to that line in the future. If you want to score a “free phone” later, this particular line won’t unlock that offer.

Mind the bill: taxes, fees, and one-time setup charges

There is a $10 device connection cost at activation, with taxes and fees recurring every month. These charges are different in every plan and location. If you’re on a plan that includes taxes and fees, check whether the promo line is included in the feature; not all add-on lines inherit that tax-included treatment.

Note, too, that lines added under this promo generally do not come with bundled device protection as standard and may not qualify for certain plan add-ons. If you want hotspot allotments or international features on the free line, be sure to check those details out before you accept.

How to check your account before activating the line

To reduce your potential risk long-term, request that support apply the promo line and send you a physical SIM; refrain from activating on eSIM right away.

When the line pops up in your account portal, make sure you see that a recurring promo credit is applied and that there’s a net zero charge on your monthly bill, before taxes and fees.

Then you can wait until your next billing cycle to ensure the discount posts accurately.

If the credit doesn’t appear on the initial bill, get in touch with support before inserting or activating your SIM. Reps can take off a not-yet-activated line without too much hassle, and they can re-add it properly if you really were eligible. Take screenshots on your phone of the chat transcripts and pages from your account showing the promo code and the promised monthly cost.

Why this free-line promotion keeps coming back

Since T-Mobile began its 5G buildout, free-line waves have been something of a recurring play in the company’s playbook. (Meanwhile, by offering the add-ons, they help defend churn, pad multi-line counts, and stickiness for families and small businesses without cutting headline plan pricing immediately.) There are also some more macro-level reasons for these promotions, industry researchers have found in studying data from the past several months — and that’s the fact that they typically seem to emerge after price cuts, or when fighting back against cable mobile bundles.

The approach is consistent with the carrier’s other metrics as well. Company filings and independent tests have consistently shown T-Mobile leading in 5G availability and median speeds, from organizations like Opensignal, and the operator has emphasized postpaid growth with minimal phone churn. Free lines are a relatively cheap way to deepen that engagement.

Bottom line: a good value if that’s what you are planning

If you need to add a line for a smartwatch, hotspot, or other spare phone — and are able to live with BYOD and no device promos — the math often checks out.

Just don’t anticipate that it will actually be $0, and don’t rearrange paid lines in the 12 months after. Verify you’re eligible, send in your paperwork, and have the full bill cycle to validate the discount before you turn it on! That said, with those guardrails in place — a 36-month forced upgrade cycle and the fact that it will not be available to all customers — the returning free line promo can still be a genuinely useful perk.