Asus ROG Phone 5 product shot of the ROG LED logo
Ryan-Thomas Shaw / Android Authority

If you’re shopping for a new smartphone, chances are you’ll stumble across the term “unlocked phone.” What is an unlocked phone exactly, and how do you know if it’s unlocked? Even more, do you even want an unlocked phone, and would it be safe to use? We answer all these burning questions inquiring minds want to know.

What is an unlocked phone?

Samsung Galaxy S21 Plus display 1
Robert Triggs / Android Authority

What is an unlocked phone anyhow? In simple terms, an unlocked phone is a device that isn’t tied to one specific carrier. Typically, when you’re locked into a ball-and-chain monthly contract, the associated phone remains locked to that specific carrier’s network.

Why? Because wireless carriers sell phones at a discount. To recover financial losses from subsidizing, carriers lock customers into a multi-year contract of device payments while locking the phone to its network. This prevents customers from getting a discounted phone and jumping networks without paying off their phones.

That said, you can’t install SIM cards from competing networks and expect instant connectivity. Even if the phone has the hardware to support other networks and you’ve made all the payments, it usually remains carrier-locked until you pay it off or meet certain requirements.

Here are links to the unlock requirements for the three major carriers in North America:

Of the three, Verizon is the only carrier that doesn’t lock phones even if contracts and payment plans aren’t complete. This stemmed from Verizon’s agreement with the Federal Communications Commission (FCC) when it acquired block C spectrum. However, Verizon does lock your phone for the first 60 days after purchase. While it’s not perfect, 60 days is much shorter than the competition.

In addition to postpaid plans and phones, restrictions also apply to prepaid plans and associated devices purchased through wireless carriers. These phones do not have payment plans, but carriers still want time and financial investments before unlocking these devices.

Unlocking versus jailbreaking

One of the big errors we see is the term “jailbreak” (or even rooting) incorrectly associated with unlocking phones. Jailbreaking specifically pertains to software, as you remove the phone’s media restrictions to install a different operating system or delete/hide unwanted pre-installed apps that you’re stuck with. To that extent, you are “unlocking” the phone’s true potential or “unlocking” it from software-based restrictions, but it’s still not carrier unlocked.

Typically, phone locking starts on the SIM card level to accept a specific mobile network code. But the other half of that restriction stems from your phone’s International Mobile Equipment Identity number (IMEI). This number is unique to each phone and used to identify all devices accessing terrestrial cellular networks, including smartwatches, laptops, modems, tablets, and more.

Moreover, all IMEI numbers have linked codes used to unlock a phone. Manufacturers store these codes in a database accessible by carriers and other third-party services. This prevents you from ripping the SIM card out of the Galaxy S21 you’re currently buying through AT&T and use it on T-Mobile’s network. The IMEI number is still tied to AT&T; thus, the only way to unlock the phone is to make all the payments, send AT&T an unlock request, and get the unlock code.

According to a quick chat with T-Mobile, you can take this route or allow the carrier to pay up to $650 in device and termination fees. In turn, you must give T-Mobile the phone and purchase a new device through the company.

You can buy unlocked phones

Google Pixel 5 vs Apple iPhone Pro EOY 2020
Robert Triggs / Android Authority

You can get a carrier-free phone from most retailers, including Amazon, Best Buy, Target, Walmart, and more. You’ll pay full price upfront versus the typical payment plan through carrier contracts; thus, the fancier the phone, the bigger the bite from your wallet.

For instance, you can get factory-unlocked versions of the Samsung Galaxy S21, the Sony Xperia 1 III, Google’s Pixel 5, and even Samsung’s Galaxy Note 20 Ultra. Gamers can grab the unlocked Asus ROG Phone 5 for $799.

But before you purchase an unlocked phone, you need to see if it’s compatible. Wireless networks in North America use two different standards: Global System for Mobile (GSM) communications used by AT&T, T-Mobile, and a few prepaid carriers, and Code Division Multiple Access (CDMA) used by Verizon, U.S. Cellular, and other prepaid carriers. Most carriers outside the United States rely on GSM networks, as the founding GSM Association is an international organization originally established in 1987.

Due to these two separate standards, a phone built specifically for Verizon may not have the bands needed to support AT&T and T-Mobile. The good news is that you can find phones that support both GSM and CDMA connectivity, but you’ll need to dig deeper into the phone’s hardware specifications before investing.

Here we run into step 2 of the compatibility roadblock. While AT&T and T-Mobile provide GSM-based cellular networks, they own and use different radio frequencies. T-Mobile openly provides its frequency list here, while you can find the other three here along with many other carriers like FreedomPop, Google Fi, Straight Talk, U.S. Cellular, and more. You’ll need to verify that the supported frequencies of the phone match the target carrier frequencies.

“Even if your phone, tablet, or mobile Internet device is compatible with carriers, your device may not operate the same on a different mobile carrier’s network,” T-Mobile warns regarding device compatibility.


Huawei mate 20 Pro - Nano Memory card in the SIM tray slot.

Short for Subscriber Identification Module, the SIM card stores what your phone needs to access a specific network. This data includes your mobile subscriber identity number, encryption keys, contacts, SMS messages, and more. It’s a small, physical card that typically fits into a pull-out slot on the side of your phone. When you swap wireless carriers, you swap SIM cards as well.

Originally introduced in 1991, newer, smaller generations are typically released every six to eight years. What we have today is the nano-SIM card introduced in 2012, measuring just over a square centimeter. Some devices also use the new embedded SIM module (eSIM) mounted inside the device, eliminating the need for swappable, disposable cards that can be lost or damaged.

Due to the difference between SIM cards and eSIM modules, check if the unlocked smartphone you want to buy includes the latter eSIM module and if your wireless carrier supports it. Recent devices packing eSIM modules include Apple’s iPhone 12 series, Samsung’s Galaxy S21 devices, select Google Pixel 5s, and the Oppo Find X3 Pro.

You’ll also find phones with two SIM card slots, allowing the device to access two separate networks. This is good for separating business and personal calls, as you’ll have two separate phone numbers. This duality also provides better coverage, as you could switch from one network to another after moving into a dead area. You can even use one SIM card locally and a separate card internationally, eliminating costly roaming fees.

Dual-SIM phones are typically sold unlocked.

How can I tell if my phone is unlocked?

If you’re currently making monthly device payments to a carrier other than Verizon, chances are the device is locked. If you paid off the device and submitted an unlock request, the first method of checking its status is to remove the current SIM card and install another card from a different network.

You can also check your phone’s unlock status using its IMEI number. Simply follow these instructions for Apple iOS and Google Android platforms:

  1. Dial *#06# to get your IMEI number in a pop-up window.
  2. Head to
  3. Enter your IMEI number.
  4. Click on the Warranty & Carrier button. However, you’ll need to create a free account to use this specific service.

If you own an iPhone or cellular-capable iPad, there’s another way to check the unlock status:

  1. Open Settings.
  2. Open Cellular.
  3. Open Cellular Data.
  4. Cellular Data Options should be present on an unlocked phone.

Again, if your qualified phone is locked to a specific carrier, you’ll need to send an unlock request. The required information includes the device IMEI number, your account number, the account owner’s social security number, phone number, and overseas deployment papers if needed.

The method of unlocking a phone using a code depends on the device. After requesting an unlock for an Android phone, customers receive a code from the carrier through a text message and an on-device pop-up window. The customer then shuts down the phone, removes the first carrier’s SIM card, installs the second carrier’s SIM card, powers on the device, and follows prompts to enter the unlock code.

Another route is to use a special app supplied by carriers. For example, Cricket Wireless provides the myCricket app with an “Unlock Device” option on the app’s sign-in screen. Once the app receives the required code, customers must reboot the phone to complete the unlock process.

In addition to carriers, third-party services can unlock your phone, but doing so could violate your contract. For Android phones, you pay a flat fee in return for an unlock code. These third-party services have access to databases managed by phone manufacturers that contain unlock codes tied to the device IMEI. But be careful: Some third-party services may not be legit and could run with your money.

Unlocked means freedom

Data recovery phonecall

Hopefully, you now have a better understanding of what “unlocked” means regarding phones and how to tell if your current device is locked to a specific network. With an unlocked phone, you have the freedom to choose the best compatible wireless carrier. Even if you paid off the phone and completed contact obligations, the device is all yours, and you should have the freedom to switch. Call your carrier today if you’ve met all the required obligations.