Why unlock your Samsung Galaxy S3 to use with a different SIM card? One possible reason is that you love your phone, but not your cellular provider because of the poor service or an unreliable connection. If you purchased a Samsung GS3 with AT&T, T-Mobile, etc. on a contract, it might be locked for a specific amount of time called the contract period.
After the contract period, you may request your network provider to unlock your phone, but it's not as easy to unlock as you think. In the U.S., unlocking became illegal after January 26th, 2013. However, a new bill is in progress to make it... more