Major cellular phone service providers may unlock phones for their customers for free as of 2015. However, some companies may have restrictions on when, how and which phones they unlock for customers.
Cellular phone carriers typically provide unlock codes for a particular phone upon request, though requests may take two or more business days to process. They can also unlock tablets that were purchased to operate with the carrier's cellular network. A cellular carrier usually requires that the phone that is the subject of an unlock request not be reported lost or stolen and that the device not be associated with fraudulent activity. In most cases, carriers also require that any contract commitments for the device have been concluded, so it is not possible to purchase a phone on a two-year contract and have it unlocked one year into the contract without paying an early termination fee under most circumstances.
There may be other restrictions on free phone unlocks that vary from carrier to carrier. For example, AT&T requires that any bills be paid in good standing for the past 60 days for customers on post-paid accounts. For prepaid customers, the phone must have been in service with AT&T for six months before the company grants device unlock requests.