Could i use an AT&T and T-mobile phone for simple mobile?

[Daissieee]

I have a phone and its AT&T and T-mobile. Could i use that phone and use simple mobile ?

 

[tasteyy]

Unlock code

I have a phone and its AT&T and T-mobile. Could i use that phone and use simple mobile ?

You need to Unlock the Mobile Phone from network lock...Without unlocking you can't use with other GSM Network Sim card....My friend Karthik Unlocked the Phone from network lock using the Free Unlock code from the site Unlocking4free.com/free-unlocking-tools now he is using the Old Phone with other GSM Network Sim card... If you need to use any GSM Network Sim card in the Phone means unlocking is must .