New rules requiring U.S. carriers to unlock out-of-contract phones now in effect

America's top wireless providers can no longer refuse to unlock devices for customers who have paid financing plans in full or completed their contract term under a new set of industry rules — agreed to over one year ago — which go into effect today.

As part of the pact, AT&T, Sprint, T-Mobile, U.S. Cellular, and Verizon, and will notify active customers whose devices are eligible for unlocking. Those who have purchased a used, carrier-locked device can also have those unlocked for a "reasonable fee."

The carriers will respond to all device unlock requests within two business days, though the actual unlocking time may be slightly longer. Military personnel being deployed overseas can have their device unlocked at any time, as long as their account is in good standing, by showing their carrier their deployment papers.

Prepaid users will not be left out in the cold. Those customers can have their devices unlocked "no later than one year after initial activation, consistent with reasonable time, payment or usage requirements."

The big four carriers and U.S. Cellular agreed to the new rules in late 2013 as part of the CTIA Consumer Code for Wireless Service. They pledged to implement at least three of the rules by May of last year, and to be in compliance with all of them by today.

Unlocking policies for AT&T, Sprint, T-Mobile, U.S. Cellular, and Verizon are now available on their respective websites.