Hi,

Let me give you a little background and then some solutions. This is generic because I don't know of T-Mobile since they are merging with AT&T. So I'll provide the AT&T information.

Phones are naturally unlocked, but a service provider might lock them

When originally manufactured, all GSM cell phones are unlocked. That is, they can be used with any SIM from any cellphone service provider - always assuming, of course, that the cellphone service provider has compatible GSM service on the same frequency bands that the phone can operate on.

Most cell phone service providers electronically 'lock' the phone so that it can only be used with their service. There are obvious reasons why they choose to do this - in particular, to force you to pay what are usually very high roaming charges when you take your phone out of their network and use it elsewhere in the world.

Fortunately, this locking is reversible. With some phones, it is possible to simply enter an unlocking password code into the phone and it is immediately then unlocked. Other phones need to be connected up to a special unlocking >Free Unlock Codes ,
● Pay $3.89 at the following website: www.theunlockshack.com/.

I trust that this is helpful and solves your problem. All the best

Ben