If you have bought a new iPhone or upgraded your old iPhone from AT&T, then you probably have a locked phone in your hands. Locked iPhone means you cannot use any other SIM card, whether domestic or international in your iPhone. Don't worry; it's quite simple to get unlocked codes from AT&T after following their procedure.
Before you move ahead with the process, you should probably check the requirement to be eligible to unlock the iPhone:
#1. The iPhone should not be reported as stolen or associated with any illegal or fraudulent activities.
#2. You should have paid the entire outstanding amount to AT&T along with iPhone installments if any.
#3. In case you have recently upgraded your iPhone, then you'll have to wait for 14-days before you can request unlock codes.
Apart from these requirements, there are also different criteria for different AT&T subscribers. It would be better to check their eligibility page for more details.
Now that you know the basics, let’s move forward with the procedure to unlock your iPhone:
How to Unlock AT&T iPhone
Step #1. Either on your iPhone/iPad or Mac/PC, launch the browser and go to att.com/deviceunlock.
Step #2. Read the requirement and eligibility details and then check the box at the end to agree with it. Click “Continue” on the opposite side of the checkbox.
Step #3. Fill up the form with relevant details and submit it.
Step #4. AT&T will send you a confirmation email along with your unlock request number. You'll need to select the link within 24 from the receipt of the email.
Step #5. You can expect a reply from the company within two business days. In addition, AT&T will also send you instruction for unlocking your device, only if the application is approved.
Please note that the final authority to unlock your iDevice rests with the company. You may also need to fulfill some of the additional procedure to get your device unlocked.
That's it; if everything is perfect from your side, then you shouldn't have any problem unlocking your iPhone.