Until recently, if you wanted to unlock your phone in order to switch carriers, there was a good chance that you'd have to do it without the cooperation of the carrier you were with. You could search online for the codes that might unlock your device -- or try to hack it in other ways. But what you usually couldn't do was call your carrier and ask how to do it.
As of February 11, 2015, that's all changed. Back in December of 2013, the major U.S. carriers set a voluntary deadline for a date by which consumers would be able to unlock their phones -- provided they met certain criteria. (And provided that the carriers follow their own rules, which has been disputed by at least one researcher.) Tablets can be unlocked as well, and the rules for unlocking are the same as for phones.
So what are the new rules? Computerworld has put together everything you need to know about unlocking your phone, including how to find out if your phone is eligible for unlocking, how to unlock it with the major carriers, and how to move your phone from one carrier to another.
Check whether your phone is eligible for unlocking
Before getting started, you first need to know whether your phone is eligible to be unlocked. Yours might not be. If you bought your phone via a two-year contract from a mobile carrier, your phone is considered a "postpaid" device. You'll have to wait until your contract is up before you can unlock your phone. There's an exception, however -- if you're willing to pay an early termination fee on your contract, you'll then be eligible.
If you bought your phone outright, it's considered a "prepaid" device and can be unlocked one year after its initial activation. There's one caveat, however: Your bill from your carrier has to be paid. So if you owe money, your carrier doesn't have to unlock your phone.
In either case, if your phone is eligible for unlocking, your carrier has to notify you. Typically, it will be shown on your bill.
Your phone needs to work with your new carrier
Presumably, you're unlocking your phone because you want to use it with a new carrier. Keep in mind that not all phones work on all networks, because some networks use different cellular technologies than others do.
U.S. cell phone networks use either CDMA (Code Division Multiple Access) or GSM (Global System for Mobiles) radio systems. Sprint and Verizon use CDMA, while AT&T and T-Mobile use GSM. Theoretically, a CDMA phone shouldn't work on a GSM network, and vice versa. But real life is more complicated than that. Phones that use the high-speed 4G LTE wireless standard should be able to work on any network, whether they are GSM or CDMA. However, not all 4G LTE phones work on all LTE bands, and so it's possible that a 4G LTE phone will not work on a specific network.
So before unlocking, check with your new carrier and make sure your phone will work with it.
You won't pay a cent for the service...
How much will this cost you? Nothing -- you should pay zilch. The FCC has banned service providers from charging for unlocking your phone.
...although there are exceptions
If you're not a customer of the carrier that the phone is locked to, you might be charged a fee. You'll have to check with the carrier for details. Also, if you use a third-party unlocking service such as a kiosk, it might charge you a fee.
Make sure you understand how to unlock your phone
The exact process of unlocking phones can vary from carrier to carrier. In some instances, you may be provided with an unlock code, or it can be done with a software update. Some providers might require that you come to a store to unlock your phone, while others will do it remotely.
Here are the specifics for the four major carriers:
With AT&T, you fill out a Web form on the company's Consumer Device Unlock Portal to ask that your phone be unlocked. Make sure that you have your phone's IMEI number (a 15-digit number). How you find that number can vary from model to model, but on just about any phone, you can find it by typing in this sequence: *#06#. You probably won't have to tap the Send or Call button. The number will likely simply appear.
If you want more information about how to unlock your phone with AT&T, head here.
You can unlock your device from Sprint either by calling 888-211-4727 or via a Web chat. In some instances, for "devices launched after February 2015," in Sprint's words, your phone will be automatically unlocked as soon as it's eligible. Check out Sprint's general information about its unlocking policy and FAQ for more details.
If you have a Verizon phone, it may already be unlocked. Verizon's online documentation for unlocking says that it doesn't lock most of its phones or tablets. It notes, "We do not lock our 4G LTE devices, and no code is needed to program them for use with another carrier. We do not lock our 3G devices, other than our non-iPhone Global Ready 3G phones." If you do have a Verizon phone that's locked, call 800-711-8300 and ask for a SIM unlock.
Your new carrier may require some steps as well
In some instances, you may need to program your phone to work with another carrier after you unlock it. For example, to program a Verizon non-iPhone Global Ready 3G phone to work with a different carrier, you'll need to use either the code 000000 or the code 123456. Check with the carrier you're leaving and the carrier you're moving to for details.
For more information
There's plenty of information online about the ins and outs of unlocking your phone. The FCC's page Cell Phone Unlocking FAQs is a great place to start. Also worthwhile is the FCC's encyclopedia entry for cell phone unlocking.
If you're interested in knowing whether or not your carrier has been keeping its promise about enabling customers to unlock their phones, you can check the Cell Phone Unlocking Scorecard to see how it's done up to now.
Finally, if you enjoy weeding through legalese and want the full story on unlocking, head to the unlocking guidelines set by CTIA - The Wireless Association for the guidelines that service providers follow.