How To Check Which Carriers Will Work With Your Phone

Before buying or selling a phone, it’s important to know what mobile carriers the phone is compatible with. Keep reading to learn more about the different types of mobile carriers and how to tell which carriers work with which phones.

What are the four major carriers, and what are MVNOs?

In the United States, there are four major carriers that own and operate cellular networks. The Big Four, as they’re often called, are AT&T, Verizon, and the now-combined T-Mobile and Sprint. (While T-Mobile and Sprint have officially merged, they still operate on two different networks for now, though they are working to combine the two over time.)

MVNOs, or Mobile Virtual Network Operators, are smaller carriers that don’t actually own any hardware and, instead, lease cellular coverage and data bandwidth from the Big Four. Some MVNOs are owned by one of the big carriers, such as AT&T owning Cricket Wireless, while others are independent entities, like Republic Wireless or U.S. Cellular.

Since MVNOs have to share the bigger network’s bandwidth, there are sometimes restrictions in terms of speeds or support. These limits are usually offset by their flexibility and attractive pricing options, with most MVNOs operating with no-contract prepaid or “pay as you go” billing.

Which networks do MVNOs operate under?

Some MVNOs operate only on one major carrier’s network, while others roam on multiple. The major carrier that an MVNO is under also tells you the type of cellular network it operates on: GSM or CDMA.

See what MNVOs operate on the Big Four’s networks from the chart below!

check network carriers

Before I buy, how can I check what carriers my phone will work with?

If you’re interested in buying a phone, checking carrier compatibility depends on whether it is an unlocked phone and what type of network it supports. This information should be included in the product listing.

If it is locked to an MVNO, then the phone will only work on that carrier. So, a Cricket-locked phone will only work on Cricket and will have to be unlocked before it can be used on other carriers.

If it is locked to a Big Four carrier, then the phone should work on that carrier, as well as most of the MVNOs under it, especially if the larger carrier owns it. In the case of Sprint, because of the recent merger, Sprint-locked phones now will also work on T-Mobile and its MVNOs. Always be sure to check with your particular MVNO or prepaid carrier to check SIM requirements and ensure the device will work.

If it is listed as unlocked, then it is not tied to any carrier. However, you’ll have to check whether the device is GSM or CDMA compatible. Most newer phone models are compatible with both GSM and CDMA networks and will work with any carrier. Older models may be restricted to just one of the two. If that is the case, you can use the chart above to see which carriers the device works with based on whether it is GSM Unlocked or CDMA Unlocked. For example, if it is GSM Unlocked, then it’ll work on AT&T, T-Mobile, and the MVNOs under those carriers.

Before I sell, how can I check what carriers my phone will work with?

As a seller, you’ll need to know what carriers your phone is compatible with so that you can accurately communicate that information to potential buyers.

First, determine whether your device is locked or unlocked and what type of network it is compatible with (GSM or CDMA). Our post, How Do I Know If My Phone Is Unlocked?, explains and breaks down the process step-by-step.

If your phone is locked to an MVNO, you’ll need to specify that it will only work on that carrier.

If your phone is locked to a Big Four carrier, then you should list it as locked to that carrier (i.e. “Verizon Locked”). There’s also a good chance that your phone will also work on the MVNOs that operate on your carrier’s network, especially if the MVNO is owned by the big carrier. For example, an AT&T-locked phone will work on Cricket Wireless and a T-Mobile-locked phone will work with Metro. Noting this fact can be helpful to potential buyers, though they should also be encouraged to check with their carrier.

If you don’t know what wireless carrier your phone is locked to, contact your carrier’s customer service to find out.  Some major carrier’s service numbers are:

  • AT&T: 1 (800) 288-2020
  • T-Mobile: 1 (800) 937-8997
  • Sprint: 1 (800) 382-3312
  • Verizon: 1 (800) 922-0204
  • Metro by T-Mobile: 1 (888) 863-8768
  • Cricket Wireless: 1 (800) 274-2538
  • Mint Mobile: 1 (800) -683-7392
  • Straight Talk Wireless: 1 (877) 430-2355

If your phone is unlocked, then you should list as unlocked and note whether it is GSM or CDMA compatible. You can follow the steps outlined in this post to determine compatibility.

Unlocked phones that work with GSM and CDMA networks should be listed as “GSM & CDMA Unlocked” and classified as compatible with AT&T, T-Mobile, Sprint, and Verizon!

Unlocked phones that are only GSM compatible should be listed as “GSM Unlocked” and classified under AT&T and T-Mobile.

Unlocked phones that are only CDMA compatible should be listed as “CDMA Unlocked” and classified under Sprint and Verizon.