T-Mobile charges $25 to $35 per month to add a line, depending on your plan

The cost of adding a line to T-Mobile depends on which plan you have. Most people on T-Mobile's main plans pay between $25 and $35 per month for each new line. If you're on an older plan or a special promotion, your price might be different. T-Mobile doesn't charge a separate setup fee to add the line itself — you only pay the monthly service cost.

The exact price also depends on whether you bring your own phone or buy a new one from T-Mobile. If you buy a phone, you'll pay the device cost upfront or in monthly installments on top of the line fee. If you already have a compatible phone, you only pay the monthly line charge.

Key Takeaways

  • Adding a line to T-Mobile costs $25 to $35 per month depending on your current plan, with no separate setup fee.
  • The monthly cost is the same whether you add a phone line, tablet line, or smartwatch line — the device itself is what costs extra.
  • You can add a line online through your T-Mobile account, in a T-Mobile store, or by calling 611 from your T-Mobile phone.
  • Promotional pricing sometimes reduces the per-line cost for a limited time, so ask about current offers when you add the line.

How much each T-Mobile plan costs per additional line

T-Mobile's main consumer plans are Essentials, Magenta, Magenta MAX, and Go5G. Each plan has a different base price, and adding a line costs a set amount on top of that.

On Essentials, the cheapest plan, adding a line costs $25 per month. On Magenta, it costs $25 per month. On Magenta MAX, adding a line costs $35 per month. On Go5G, the newest plan, adding a line costs $35 per month. These prices assume you're paying full price with no promotions. If you're on a business plan or a plan from a few years ago, the per-line cost may be different — call T-Mobile at 611 or visit a store to confirm your plan's pricing.

What you need to do to add a line

You can add a line three ways: online through your T-Mobile account, in a T-Mobile store, or by phone. Online is usually the fastest if you already know which plan you want.

To add a line online, log into your T-Mobile account on the T-Mobile website or app, go to your account settings, and look for "Add a line" or "Manage lines." You'll be asked whether you want to bring your own phone or buy a new device. If you bring your own phone, you'll need to know the phone's IMEI number (found in the phone's settings under About Phone). If you buy a device, T-Mobile will show you the cost and let you choose a payment plan. After you complete the order, the line usually activates within a few hours.

If you go to a T-Mobile store, a representative can add the line for you and help you choose a phone if you need one. If you call 611 from your T-Mobile phone, a representative can walk you through the process over the phone. Both methods take longer than online but may be easier if you have questions.

Phone costs when adding a new line

If you already own a phone you want to use, adding a line costs only the monthly service fee — nothing more. You just need the phone to be compatible with T-Mobile's network and unlocked (or already on T-Mobile). You can check compatibility on T-Mobile's website by entering your phone's model.

If you buy a phone from T-Mobile when you add the line, you'll pay the full price of the phone upfront or in monthly installments. A new iPhone typically costs $800 to $1,200 depending on the model. A new Android phone typically costs $300 to $1,000. T-Mobile sometimes offers discounts on phones when you add a new line, especially if you trade in an old phone. Ask about current phone promotions when you add the line.

Promotional pricing and discounts

T-Mobile regularly runs promotions that reduce the cost of adding a line for a limited time. These promotions might offer a discount on the monthly line fee for the first few months, a free line for a certain period, or a discount on a phone when you add a line. Promotions change frequently and vary by region.

To find out what promotions are currently available, check the T-Mobile website's promotions page, ask in a T-Mobile store, or call 611. If you add a line and a promotion starts the next week, T-Mobile usually will not retroactively apply it to your account, so it's worth asking about upcoming promotions before you commit.

Adding lines for tablets, smartwatches, and other devices

You can add a line for a tablet, smartwatch, or other connected device, not just a phone. The monthly cost is the same as adding a phone line — $25 to $35 depending on your plan. You don't need to buy a new device from T-Mobile; you can bring your own tablet or smartwatch as long as it's compatible with T-Mobile's network.

To add a line for a non-phone device, follow the same process as adding a phone line. When you're asked what type of device you're adding, select "Tablet," "Smartwatch," or the appropriate category. You'll need the device's IMEI or similar identifier. The device will share your phone number or have its own number depending on the device type and your plan.

What happens to your bill after you add a line

After you add a line, your monthly T-Mobile bill increases by the per-line cost plus any device payment if you're paying for a phone in installments. If you added a line on the 15th of the month, for example, you'll be charged a prorated amount for the rest of that month, then the full monthly charge starting the next month.

You can see the new line on your bill immediately after it activates. If you're on a family plan with multiple lines, each line appears separately on your bill so you can see which devices are using data and how much each line costs. You can manage each line separately — pause it, change its plan, or remove it — through your T-Mobile account online or by calling 611.

Frequently Asked Questions

Can I add a line without buying a phone?

Yes. You can add a line with a phone you already own. The phone must be compatible with T-Mobile's network and either unlocked or already activated on T-Mobile. You'll pay only the monthly line fee, with no device cost.

Is there a setup fee to add a line?

No. T-Mobile does not charge a separate setup or activation fee to add a line. You pay only the monthly service cost for the line itself, plus the cost of a phone if you buy one.

How long does it take for a new line to activate?

If you add a line online or in a store, it usually activates within a few hours. If you call to add a line, activation may take up to 24 hours. You'll receive a text message or email when the line is ready to use.

Can I remove a line after I add it?

Yes. You can remove a line anytime through your T-Mobile account online, in a store, or by calling 611. If you're paying for a phone in installments, you'll still owe the remaining balance on the device even after you remove the line.

What if I want to add a line but keep a separate bill?

T-Mobile's standard setup puts all lines on one bill. If you want a separate bill for a new line, you can ask T-Mobile to set up a separate account instead of adding a line to your existing account. This means a separate monthly bill and separate login, but the lines won't share a plan.