Locked Phone

When you purchase a phone from a carrier like AT&T, Verizon or Sprint, the device is essentially locked to that specific carrier. If you ever want to use your phone on another compatible network or sell the device to someone else for use elsewhere, you will have to ensure that it is unlocked or sell it to someone who uses the same carrier. The process is fairly simple but may vary depending on your hardware and your original service provider.

Over the years carriers have locked devices to their networks in order to ensure that customers would fulfill their contracts or payment agreements. By locking smartphones to one carrier, the service provider has final say on which networks the device can connect to. This makes sense when considering the discounts that some providers offer when you sign up for a new phone or new service.

locked mobile phone

Certain requirements must be met before a carrier will unlock a phone and those requirements can vary depending on what type of agreement you have with the service provider. If you purchase a phone outright from a non-carrier retailer, chances are that the device is already unlocked and can be sold or transferred without any issues. However, if you purchased a smartphone through a carrier and signed an agreement, then you need to fulfill that agreement before it can be unlocked. Let’s take a look at what’s required for each carrier before the unlocking process can be done.


att globe logo image

AT&T uses a GSM (Global System for Mobile) network that is similar to T-Mobile’s network and may allow devices to easily switch between networks. GSM is also used in many other countries around the world and covers 90% of the worldwide market. AT&T has a list of requirements for devices in order for them to be unlocked. Below is a list of these main requirements:

  • Device must not be reported as stolen or lost
  • Device must not be involved in any fraudulent activity
  • Device must have ALL service commitments and install plans fulfilled and any early termination fees paid in full
  • Device must not be active on another AT&T customer account
  • Device must be designed for use on AT&T’s network

AT&T also has more instructions for unique account situations as well as a list of requirements for devices that are purchased under AT&T’s GoPhone system. For more information visit AT&T’s device unlock page here.


sprint logo plain image

Sprint uses a CDMA (Code Division Multiple Access) based network that is technically compatible with Verizon. If you are switching from Sprint to Verizon make sure to check device capabilities before unlocking or making a final decision, as not all hardware is universally transferrable between the two carriers. It has been reported that most newer iPhones and some Samsung and Motorola devices are capable of making the switch. Sprint also requires the following criteria to be met before unlocking a device:

  • Device must not be reported as stolen or lost
  • Device must have met full contract requirements with no outstanding bills or fees
  • Device must be fully paid off if purchased on Installment Billing, Sprint Easy Pay or Sprint Lease

Sprint also has a webpage with full details on specific situations and more information about unlocking your device from the Sprint network. For full details visit here.



T-Mobile, as reported above, also uses the GSM standard for their network. This allows for basic cross-compatibility with AT&T as well as the ability to work in a large selection of overseas markets. T-Mobile also has a list of items that must be met before unlocking including a few different requirements not seen at other providers. The basic eligibility requirements to unlock a device on T-Mobile are as follows:

  • Device must originally from T-Mobile
  • Device must not be reported as lost, stolen or blocked
  • Device account must be in good standing and not canceled
  • No more that two mobile device unlocks per line of service within 12 months
  • Device must satisfy all Postpaid or Pay in Advanced general terms
  • Device must be active on T-Mobile network for minimum of 40 days before unlocked
  • Device associated with account must be zero including pending charges

T-Mobile allows for certain military exceptions as well as exceptions related to Business and Government accounts. To see more information on requirements or how to request an unlock for a T-Mobile smartphone, click here.


verizon transparent logo

Verizon works on a CDMA network so Verizon devices are not as inherently compatible as other GSM devices. A few smartphones have cross-compatibility or have multiple SIM slots to be used across multiple networks, but most of those devices fall under the pre-paid or unlocked category. Be sure to check your device documentation as well as Verizon’s requirements before unlocking, to determine what, if anything, is required to unlock your device. Basic Verizon requirements before unlocking a device are as follows:

  • 4G LTE postpaid devices are not locked and no code is needed to program them for another carrier
  • 3G postpaid devices are not locked and a simple code of 000000 or 123456 is required to unlock
  • 3G prepaid devices are not locked and a simple code of 000000 or 123456 is required to unlock
  • 4G prepaid devices are not locked and require nothing to use elsewhere (minus “Phone-in-the-Box” prepaid devices–which require service for 1 year or payments in the amount indicated on packaging

Military Personnel can request devices to be unlocked for certain situations by contacting Verizon customer service. Verizon also notes on their Unlocking Support page that the unlock process only disables software to allow the device to be used on another network but does not automatically guarantee the device will be compatible on other networks (CDMA vs. GSM).

customer support rep representatives
Calling into customer support is often times your best bet

Today there are so many different types of wireless devices across many different providers as well as a handful of options on how to purchase a cellular device. This creates some confusion on how each device can be unlocked or if it’s even necessary. Following the guidelines listed above will set you in the right direction. Be patient and persistent as well as thorough when attempting to unlock a device. As long as the proper requirements have been met you should find that most carriers are very helpful when unlocking a smartphone.


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