How to Get an Unlock Pin for an AT&T SIM Card

by Bruce Traxby

Many people smartly protect their SIM cards with a PIN number, because this protects intruders from using your SIM card in their own phone; they can peruse through your contacts and effectively steal your cellular and/or data service. However, instances inevitably arise where you forget your PIN number, or your SIM card is simply unresponsive. Fortunately for such cases, AT&T can provide you an unlock PIN for your SIM card and allow you to use your phone with full functionality once again.


Step 1

Set up an AT&T online wireless account, or log on to your existing one. If you're setting it up for the first time, you will need identifying information, such as your phone number, address and the last four digits of your Social Security number.

Step 2

Obtain the unlock code for your SIM card by selecting your device under the "My Services" section of your account. After clicking "Unblock SIM card", the PUK (Pin Unlock Key) code will appear.

Enter your PUK code in the SIM settings of your phone. If you don't know where to find this, click the "AT&T: Phone/Device Support" link under Resources to locate your user manual.


  • A SIM PIN is a four- to eight-digit code that is used to prevent unauthorized use of a SIM card. The default PIN for an AT&T SIM card is 1111. When the SIM PIN is enabled, the security option follows the SIM card if the card is moved from one device to another. SIM cards are locked following three successive incorrect PIN entries. To unlock your SIM card, you will need a PIN Unlock Key (PUK) code from AT&T.
  • If you are still unsuccessful in unlocking your SIM card after following the steps provided, contact AT&T either by phone or by going into your local AT&T store. They can provide more detailed information that may be pertinent to your specific type of phone.


  • Do not attempt to enter a PUK code unless directed to do so by an AT&T customer service or technical support representative. Entering a PUK code incorrectly more than 10 times will cause the SIM card to lock permanently.

Items you will need

  • Account information

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