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Should I Buy an Unlocked Phone?

Mobile phone lying face up on a table with an unlocked padlock on the screen

Before we can discuss the advantages and disadvantages of unlocked phones, we need to understand what it means for a phone to be "locked" or "unlocked."

In a nutshell, practically all phones sold through carriers (and some phones sold by manufacturers and retailers) are "locked" to a particular provider's network. If you try to use them on another provider's network, they will not work.

"Unlocked phones" are either previously-locked phones that have been unlocked by their carriers (or occasionally by someone else who knows how to do it), or phones that were sold as unlocked by their manufacturers. In theory, unlocked phones can be used on any carrier's network. In practice, it's not quite that simple.

Let me explain it to you.


Will Any Unlocked Phone Work on Any Carrier's Network?

The short answer is a no. Despite what you may have heard or read, not every unlocked phone will work on every phone company's service. If you're considering buying an unlocked phone, you'll have to do your homework in advance to make sure that the phone you buy will work on your carrier's network. Here are some things to look for.


Using Unlocked Phones on CDMA Networks

If your carrier is a current or former CDMA network (for example, U.S. carriers Verizon, Sprint, and US Cellular, as well as their MVNO's), then you cannot use an unlocked phone unless the carrier has certified that phone to work with their network. It doesn't matter if the phone is perfectly capable of working on the network. Until the carrier certifies it as compatible, they won't activate it.

Legacy CDMA wasn't designed around a common set of standards like GSM was, and GSM phones were never compatible with CDMA. It was therefore necessary to have a database of phones that were known to be compatible with a CDMA operator's network, and that the activation and provisioning system check for compatibility before accepting a device on the network. Even though CDMA itself is being phased out, the legacy activation system lives on.

If Verizon is your carrier, then you may have difficulty activating an unlocked phone on their network even if it has been certified. The procedure for activating a CDMA-less phone on VZW isn't very intuitive for the support techs, and many of them have a hard time finding it the first time they do one.

Fortunately, there's a shortcut to getting your unlocked, certified phone to work on VZW that usually works. Tell the support tech to activate "Feature 83856" on the account, and then to sync the network profile with the billing profile. Feature 83856 is the code that instructs the system to activate the phone as a CDMA-less device and to route all voice calls over LTE. Once that feature has been activated, reboot the phone, and it should work.


Using Unlocked Phones on GSM Networks

Most mobile phone providers throughout the world, except in the United States, use GSM. In the United States, AT&T and T-Mobile use GSM, as do the MVNO's that piggyback on their networks (Cricket, H2O, RedPocket, Mint Mobile, etc.).

The GSM standard requires that carriers accept any compatible, unlocked GSM phone onto their networks. This gives users a lot more freedom in choosing their devices. It also simplfies activation: Install your SIM card in the phone, turn it on, and nine times out of ten it will work, with no manual configuration needed. But that assumes that the phone is compatible with the particular GSM carrier, which is something you should determine before you buy the phone.

Choosing a Compatible Unlocked Phone for Your Carrier

The most important compatibility factor to look for when buying an unlocked phone is that it supports your carrier's bands. Mobile phones are radio devices. In order for them to be able to access a network, they must have radios that work on the frequencies used by the mobile phone company. This is a hardware factor, so it's not something that an update will fix. Either the phone has the radios needed for your carrier's bands, or it doesn't. Obviously, you want to make sure it does before buying the phone.

Few (if any) phones can access all of the bands used by every carrier in the world. What's important is to make sure the phone you buy can access the bands that your carrier uses. If you plan to use your phone on more than one carrier's network, then you have to check compatibility for all the carriers.

One useful tool for determing band compatibility is FrequencyCheck. In my experience, it's usually pretty current. But it's still a good idea to check with your carrier to make sure a phone will be compatible with their service before buying the phone. You can also check whether other people using your carrier have had a good experience with a phone by checking on your carrier's forum or Howard Forums.

Many unlocked phone models also have regional variants that differ mainly in the bands they support. If the phone you're considering has regional variants, start by checking the specs for the variant designed for the region where your phone will be used. Most regional-variant phones support most (or less often, all) of the bands used by the most important carriers in those regions.

Once you find a phone or variant that supports the bands you need, make sure to order that exact phone or variant. Check the model number and UPC code, not just the model name. Most phones have model names that are the same across all variants. The model numbers and the UPC codes, however, will be specific to a variant. Likewise, check the phone's model number and UPC code when you receive it to make sure you got the one you ordered. Shipping mistakes happen.

It's not strictly necessary that a phone support all of the bands a carrier uses. But it should support all of the required ones, and as many of the optional ones as possible. Ask your carrier which bands are essential, and at a minimum, make sure that those bands and as many of the non-essential ones as possible are supported. The more of the carrier's bands a phone supports, the better it will work, and in the most places.


Advantages of Unlocked Phones

Let's begin by looking at some of the reasons why many people, including myself, prefer unlocked phones:


Potential Disadvantages of Unlocked Phones


Here's what it comes down to in the end: If your carrier sells a phone that you like, and if you like your carrier and plan to stay with them anyway, then buying a phone from your carrier may be a better option for you. You're guaranteed compatibility and support, warranty repairs are simpler, you don't have to worry about a routine update hosing your phone's network compatibility, and you may even get a discount or special financing.

If, on the other hand, you're not happy with your carrier's selection of phones (or with the carrier itself), if you move or travel a lot and don't want to be tied to a particular carrier, if you need a dual-SIM phone, if phones are your hobby, or if there's a particular phone that you just love but that your carrier doesn't sell, then maybe you should look into an unlocked phone.

By the way: My primary phone is a dual-SIM, unlocked, OnePlus 7t; and my primary phone carrier is AT&T Prepaid.