How to Unlock a SIM

Written by Nicole Levine, MFA

Last Updated: March 28, 2024 Fact Checked

Protecting your SIM card with a separate password can help thwart anyone's attempts to use your SIM in another device. But what if you need to switch phones and forgot your SIM card password? The only way to unlock a password-protected SIM is to get a special code called a PUK (PIN unlock key) from your mobile provider. The provider may need you to prove your identity to give you this code. This wikiHow teaches you how to use a PUK to unlock your SIM card.

Steps

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1
Enter your SIM unlock code. If you locked your SIM card, you will be prompted to enter the password when you insert that SIM into a new phone. If you know the password, enter it to unlock your SIM. If not, you can unlock the SIM with a PUK (pin unlock key) that comes from your mobile provider.
- 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]
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  Research source} If you don't know the PIN, try the default code first.^{[2]
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  Research source} After you enter the code incorrectly too many times (the number varies), you'll be prompted to enter the PUK.
2
Get the PUK for your SIM. This code comes from your mobile provider, so you'll need to contact them directly.^{[3]
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Research source} Your provider may ask for the number on the SIM card, so write that number down before you contact them by phone.
- 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]
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  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).
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The PUK is typically 8-digits long. Be careful when entering this code—if you are unable to enter the correct PUK after 10 attempts, your SIM will be deactivated and you'll need to get a new one from your provider. After you successfully enter the code, you will be prompted to create a new SIM pin.^{[5]
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Even if you want to disable the PIN, you'll need to create a new one before you can disable SIM locking. This time, write down your PIN so you have it in case you lose it.^{[6]
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5
Disable SIM locking (optional). If you don't want to use a SIM PIN in the future, here's how you can disable SIM lock:
- 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.^{[7]
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- 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.^{[8]
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