What Does GSM Unlocked Mean? [All You Need To Know]

Deyan Georgiev
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Updated · Apr 20, 2023

Deyan Georgiev
Website Manager | Joined October 2021

Deyan has been fascinated by technology his whole life. From the first Tetris game all the way to Fa... | See full bio


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If you’re thinking of switching phone service providers or buying a new phone - we have many helpful details to share with you. 

Knowing the difference between a locked and an unlocked smartphone will help you make better choices when picking a new device. And depending on the advantages and disadvantages, you will make a more informed decision. 

What does GSM unlocked mean?

Let’s begin by answering this question.

What Does GSM Unlocked Mean?

The Global System for Mobile (GSM) is a network utilized by phone carriers that use Subscriber Identity Module (SIM) cards, to which phone numbers and services are linked. 

If a phone is locked, it can only work with one cell phone provider’s network. If the provider’s SIM card is removed and replaced with another’s - the device won’t operate. 

On the flip side, if you have an unlocked phone, it can work with any carrier service’s SIM card, as long as they are GSM compatible. 

Unlocked devices allow you to choose the provider that’s best for you, you can save money in the long run, and you don’t have to deal with pre-installed apps. However, you must pay the phone upfront and you won’t have a carrier warranty.

Factory GSM Unlocked Phone

A smartphone with a GSM factory unlock is manufactured and distributed without a provider contract. Such phones give users the freedom of choosing the GSM carrier that suits their needs and finances most from the get-go. It works with any GSM network and provides the most flexibility. 

And unlike with an unlocked phone by a specific carrier, you never need the original provider’s SIM card for any resets. With a factory GSM unlock, the process is easier. 

How to GSM Unlock a Phone?

There are a few ways you can unlock a GSM locked smartphone:

  • Through the service provider
  • Using specialized software
  • Through the hardware
  • Using the IMEI method

Here’s how they work:

  • Contacting your service provider is the simplest method.

Call your provider and request a phone unlock. They’ll most likely ask to confirm that you are the device owner. Upon request, you might have to wait up to 30 days for them to send you a network unlock code

Keep in mind that providers may request payment for GSM unlocks.

  • Using specialized software requires some tech know-how. 

This method requires connecting your phone to a computer to run an unlocking program.  

However, this is not advisable as it may not be safe for your device or can lead it not to work correctly.

  • Unlocking through hardware is something you can do yourself. 

However, it’s easier and safer to trust a technician. Though you are not even recommended to do this. 

If there is a mistake, your phone is likely to be damaged. Also, changing the device’s hardware means that its warranty will no longer be honored by GSM carriers.

  • Using the IMEI method is the most effective method of all. 

An International Mobile Equipment Identity (IMEI) is an identification code given to all mobile devices. Some websites can help you change your phone's IMEI database entry and unlock it.

This method is fast, affordable, and often best left for professionals.

GSM Unlocked vs. Fully Unlocked Cellphone

The difference between GSM unlocked, and factory or fully unlocked cell phones is the following:

A GSM unlocked phone only uses GSM technology and only operates with providers that support it. 

A fully unlocked phone supports GSM and CDMA tech and works under any carrier.

CDMA vs. GSM Unlock

Now you may be wondering what CDMA is. 

CDMA vs. GSM Network

Code Division Multiple Access (CDMA), like GSM, is a network used by phone carriers. They are older radio systems that only support 2G and 3G connectivity. However, they are not compatible with each other since they work on different frequencies. 

CDMA doesn't use SIM cards. Instead, it stores a provider’s network data on the phone’s hardware. Unlocking requires you to flash information from another provider’s network onto the phone.

In the past, phones supported either one or the other. However, there are new devices that support both.

Here’s the thing, though:

2G and 3G are going away! 

Providers are shutting down these networks as we speak, so if your phone does not support 4G or 5G, you need a new one soon. 

That’s right.

It might be time to part with your flip phone - and get yourself a new model like many others. Statistics show that global 5G-enabled smartphone shipments will likely reach 51% by 2023.

CDMA vs. GSM Carrier

GSM carriers are standard worldwide, while CDMA carriers primarily service the US. 

One of the best things GSM carriers offer is the ease of transferring between international networks. Users can travel without difficulty while keeping the same phone number. GSM providers also support a wider variety of phones.

CDMA carriers became so popular in the US because, at the time, they were faster, with more reliable bandwidth. This popularity is still present today, even though GSM technology has caught up.

The most popular GSM carriers in the US are:

  • AT&T
  • T-Mobile

The most popular CDMA carriers in the US are:

  • Verizon
  • Sprint
  • U.S. Cellular

How To Know if My Phone Is GSM Unlocked?

There are a few ways you can check if your device is locked or not:

  • Check your phone’s settings

The way to do this depends on the type of phone you’re using. 

If you own an iPhone, navigate to the Cellular section of the Settings app and see if there’s an option to change the Cellular Data Network. If there is - you likely have an unlocked GSM device.

Navigate to the Mobile Networks Section in Settings if you own an Android and search for available carriers. If you can connect to different networks, your device is likely unlocked. 

This is not a very reliable method, so double-check with one of the following two:

  • Switch SIM cards

Remove the SIM card in your phone and replace it with another from a different carrier. The device is unlocked if you can make calls and send texts with the new SIM card.

  • Use an IMEI checker

A good checker will not only tell you if your phone is locked but will also let you know if it's blacklisted. It’s good to know this since you cannot unlock such a phone.

Advantages And Disadvantages Of GSM Carriers

Here are some pros and cons of America’s leading GSM providers:



  • Far-reaching network coverage
  • Unlimited 5G plans with no extra costs
  • One of the fastest networks
  • Growing 5G coverage


  • Expensive plans
  • Poor customer service



  • One of the fastest networks
  • Attractive unlimited plans
  • Low-cost data plans


  • A hard cap on data for prepaid plans
  • Fewer plan options

Wrap Up

With all that said, you now know the difference between a GSM unlocked phone and a locked one. 

If you’re unhappy with your provider, you’re a step closer to changing it, and if you’re looking for a new phone, now you know a few important things to consider.


Is GSM unlocked good?

There are pros and cons to having an unlocked phone. It allows you to pick the carrier that suits you best, and there are no monthly payments or pre-installed apps. On the downside, you must pay for the phone immediately and at full price. You also don’t benefit from a carrier’s warranty.

What carriers are GSM unlocked?

The most popular GSM networks in the United States are AT&T and T-Mobile. Some of the other ones include Broadpoint, DTC Wireless, and Indigo Wireless.

Can you put any SIM card into a GSM unlocked phone?

A GSM unlocked phone can operate under any service provider, as long as they support GSM technology.

What does GSM unlocked stand for?

An unlocked smartphone can work with a SIM card of any GSM network provider. On the contrary, if a device is locked, it can only work with the carrier’s card that has it locked. This is what GSM unlocked does mean.


Deyan Georgiev

Deyan Georgiev

Deyan has been fascinated by technology his whole life. From the first Tetris game all the way to Falcon Heavy. Working for TechJury is like a dream come true, combining both his passions – writing and technology. In his free time (which is pretty scarce, thanks to his three kids), Deyan enjoys traveling and exploring new places. Always with a few chargers and a couple of gadgets in the backpack. He makes mean dizzying Island Paradise cocktails too.

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