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.
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