One of the prominent feature in this new iPhone 5 is the LTE or 4G technology which is about ten times faster as compared to previous 3G technology on iPhone 4/4S. However, some networks are providing better data volume and speed as compared to official iPhone 5 carriers such as AT&T, Verizon and many other carriers worldwide. So, if you want to use any of those carriers' SIM card on your iPhone 5, you will need to unlock it.
If you are getting Verizon iPhone 5, we have a great news for you because you will get fully unlocked iPhone 5 right out of the box and you will not need to buy the factory unlocking solution. But for other networks such as AT&T, you will need to get your iPhone unlocked before using any other carrier’s SIM card.
Currently, there is no software unlock (ultrasn0w) or Gevey SIM solution is available for current basebands 1.10.16 of iPhone 5 on iOS 6. Moreover, it is also an unreliable method, because you can’t update your firmware unless a new unlocking solution is available. However, the best and permanent solution is the IMEI factory unlocking which turns your iPhone to factory unlocked iPhone.
All you have to do is to check if the official carrier of your iPhone (the carrier that iPhone is locked to) is available in this carriers unlock list or not, then you will be requested to submit your IMEI and your iPhone 5 will be unlocked.
The best thing about this method is that your iPhone 5 will work as off-contract phone, so you can update it without the fear of locking it again.