Another free T-Mobile line for many customers


T-Mobile is back with a new free line offer this week for many customers with an existing plan with 2 paid lines (H/T: Slickdeals). Last month, T-Mobile ran a similar promotion to add a free line for those with at least 2 paid voice lines (while some plans were ineligible, many – including many older and no-longer-available plans — were eligible). I wrote about why T-Mobile customers shouldn’t have ignored that promo (See: T-Mobile customers, do not miss the free line promo). This time, some of the previous stacking opportunities are excluded, but I think qualifying T-Mobile customers should still consider this one yet again.

T-Mobile logo

Adding a totally free line to your T-Mobile account

This is now the fourth time this year that T-Mobile has offered a completely free additional phone line. I should note at the outset that not all plans are eligible for the free line. However, many (including many no-longer-available plans) are eligible.

Determining your eligibility on your own is slightly complicated. If you want to do this the “easy” way, reach out to T-Mobile on Twitter or Facebook or via the chat function in the T-Mobile app (though note that not all reps are well-informed). If you’re OK at following directions/pictures, this reddit thread tells you how to find your plan’s SOC code and this image from reddit shows you the list of qualifying SOC codes. If the keyboard shortcut for developer tools doesn’t work, after step 4, right-click your mouse (anywhere on the background of the webpage) and click “inspect” to see the developer tools shown in the screen shot.

In my case, I have an older / no-longer-available T-Mobile One plan and I was able to add a free line both when they ran the promotion this past summer and again in November and now yet again (so I now have three totally free lines on my plan). Since my T-Mobile One plan includes unlimited high-speed data (and unlimited calls/texts) for all of my lines, the free line gets exactly the same thing. It literally costs me nothing more to have an additional line with full unlimited call/text/data. An important note here is that my plan includes all taxes in the monthly charge, so there are no additional taxes for me for my free lines (but some plans break out taxes separately for each line, so a free line may actually cost you a few bucks depending on your plan). That alone seems pretty generous since it means you could potentially offer a line to a family member at no cost to you.

Why add a free T-Mobile line?

Even if you don’t think you’ll use the free line any time soon, it doesn’t hurt you to pick it up and you could add the line yourself online or via T-Mobile customer service (note that if you add it yourself online, it shows a monthly cost initially when you add the line, but as long as you’re on a qualifying plan, it will later show up in your account as being free).

Personally, I think there are a few reasons to consider adding a free line:

  • It makes a nice gift. You could offer that free line to a friend or family member. Who doesn’t like free cell phone service?
  • Additional lines for T-Mobile Tuesdays offers. Most offers have become kind of weak, but every now and then there’s a $2-$5 Dunkin or Panera gift card or something that’s even better if you can stack multiple lines.
  • Earn 4% APY with T-Mobile Money. This is basically a virtual checking account offered to T-Mobile customers. T-Mobile customers get 4% APY on the first $3K in the account provided that they deposit $200 per month (and 1% on the rest of their balance). While the cap on 4% is low, even the 1% on the remainder isn’t bad in the current environment (and 4% on $3K is worth $120 a year). That’s an added bonus that goes with the free cell service gift (or perhaps you can have multiple accounts on your own for more 4% bandwidth, I’m not sure).
  • Future porting promotions. Other carriers run deals all the time to attract each other’s customers. For example, AT&T has offered a $250 prepaid Visa to customers who port in from another carrier. You wouldn’t be able to do this right away as the terms usually state that closing a line within 90 days will convert the free line to paid, you could use this to earn a bonus down the road.

No Costco stacking this time

Last time around, I wrote about stacking a $200 rebate from Costco and a $100 rebate from T-Mobile for porting a number. This time, the promotion terms explicitly exclude stacking with the Costco BYOD promotion.

No stacking on most of the current phone offers

I’m not aware of a stacking opportunity for a free or discounted phone this time. According to the Slickdeals thread, this deal can not be stacked with any of these other current T-Mobile offers:

  • iPhone 12 “on us” (2020 Apple Trade Activate P3)
  • BOGO iPhone (2020 Apple Buy 2 P11)
  • Free Galaxy A71 5G with new line (2020 Samsung Activate P12)
  • Free OnePlus 8/8T+ 5G with new line (2020 OnePlus Activate P5)
  • Costco BYOD promos
  • TFB-exclusive promos

I don’t think there is a current deal that will stack but will update if I learn otherwise.

Bottom line

Many T-Mobile customers can currently add a totally free line to their plan again (while keeping their existing plan with no changes or deletions to their service plan). If your plan qualifies, I think it’s worth adding a line for nothing (though YMMV if you need to pay additional taxes for each line with your plan). The flip side of this is that T-Mobile may become more congested with all of these free line offers and if you start giving lines to friends or family members you may feel more obligated to stick with T-Mobile in the future. I’m personally not too concerned about that, but you’ll have to weigh the pros and cons for yourself.

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[…] Keep in mind that you can sign up for the T-Mobile Tuesdays deals with each line on your plan. In the past, I was even able to sign up with the line assigned to a prepaid hotspot by loading the app on a tablet and then logging into the hotspot in my browser to get the SMS message to verify the number. This may be useful for folks who recently added a free line. […]


I don’t believe you can add multiple T-Mobile Money accounts, I think it’s limited per social security number, not how many lines you have.


I have 2 lines with tmobile under tmobile one plan. I called tmobile and they said I need to add a 3rd line to get the 4th line free. I guess it was too good to be true

[…] Update 12/22/20: This deal is back again and valid through 12/24/20. Read more here: Another free T-Mobile line for many customers. […]


It does not work with “TMSERVE2 -T-Mobile One Military.” But, then again, I only pay $100 a month inclusive for voice, unlimited data, 5 GB hotspot, and standard Netflix. 😉




Should be compatible with 50% off Pixel and 50% off iPhone SE. You can buy another Pixel so you have something to use while the other one is in the shop 😉


I think it’s a different promo, similar result though. The 90 days you reference I believe is to add back a previously ported out number. I believe the 1st promo this year had the language that they retro actively claw back if you cancel within a year, so unless you want to retro activly pay for the free lines you are locked in for a year with T-Mobile. This is on any of your “free” lines and that year is extended based on the most recent free line add. 🙁
On the plus side after the year is up you can port out most of your paid lines (have to keep 2 paid lines at all times to maintain all free lines) and port them back into your free lines after 90 days.

Michael Barie

I got the free line and phone back in May and I am still calling every month to get the line charge off my bill.

Last edited 2 years ago by Michael Barie

If I gave the free line to someone would they be eligible to signup for Tmobile Money 4% APY?


Awesome! How does that work?? They create their own account or would they need my account info to signup?


Own account, I’ve done it with family members, doesn’t require you to give your account information.


Thank you!


I’m assuming this doesn’t work with Sprint SWAC plans?


Did you have a single line account before you added the free lines? I tried a few weeks ago at Costco and after standing around forever, she informed me the free line only comes with plans of 2 or more lines (55 plus plans excluded).


Costco is running a free Samsung A11 after rebate plus $100 shop card promo through 12/24. Tforce and the wireless rep at Costco said it’s a valid stack with the free line promo. Did it last night. The free line is showing up on my T-Mobile account this morning. Only downside is that Costco keeps low inventory on their phones. I had to call around to four different locations before I found one with an A11 in stock. Will see if the rebates go through in a few weeks!