The default SIM unlock code for T-Mobile and Sprint is 1234, while the default unlock code for Verizon and AT&T is 1111’. [1] X Research source If you don’t know the PIN, try the default code first. [2] X Research source After you enter the code incorrectly too many times (the number varies), you’ll be prompted to enter the PUK.
Since your SIM isn’t working, you’ll need to use a different phone (or a VoIP service like Skype or Google Voice) to contact customer service. Some providers, including AT&T, allow you to get the PUK online. [4] X Research source If you have AT&T, you can follow these steps to get your PUK: Sign in to your AT&T account dashboard and click My wireless. Select your locked phone under “My devices & add-ons. " Click Manage my device. Click Get your PIN unlock key (PUK).
iPhone: In the Settings app, tap Cellular, select SIM PIN, and then toggle off the switch. You will need to enter your new SIM PIN once to verify that you’re turning it off. Android: In the Settings app, tap Biometrics and security (or Security & lock screen, or similar), select Advanced or Other security settings, tap SIM card lock or Change SIM PIN, then then toggle off the switch. You’ll need to enter your current SIM PIN to confirm the change.
