Unlock Samsung Galaxy S3
This is how to Unlock your Samsung Galaxy S3 from any GSM network.
You will receive the "SIM Network Unlock PIN" message once you enter a foreign sim card. Enter the 8 digit Network Unlock Code we email to you and this will permanently unlock your Samsung Galaxy S3 to be used with any GSM carrier.
Upon placing your order for your Samsung Galaxy S3 Network Unlock Code, the Network Unlock Code will be emailed to you once it has finished processing. Once unlocked, your Samsung Galaxy S3 will be permanently unlocked for another GSM Network.
Here's a similar Samsung Galaxy S6 getting unlocked: