Enter a PIN code to lock your SIM card. The default PIN code for an AT&T SIM card is "1111". Change the default PIN code for more security. After activating SIM lock, you must enter the PIN code if you move the SIM card to another device. If you forget your SIM lock PIN code, learn how to get the PIN Unlock Key (PUK) code to unlock your SIM card. The PUK stands for Personal Unlocking Key. It is a security feature for all the modern SIM cards used in smartphones, tablets, and other devices. PUK is a unique code linked to your SIM card. Sometimes it is also known as PUC (Personal Unlocking Code). It is generally 8 digits long. Step 4: To change the existing SIM PIN code, go to the SIM card lock settings and select "Change SIM PIN." Step 5: When asked to enter your old SIM PIN, enter the default PIN. Then press OK. Step 6: Enter the New SIM PIN you want to use next. You can select a code length of four to eight digits. When you're finished, press OK. Every SIM card will have a Personal identification number (PIN) and a Personal unlock key (PUK) code. If you enter the wrong SIM pin more than three times, you need a PUK code to unlock a SIM. And, multiple incorrect PUK code entries might permanently disable the SIM card. Consider PUK codes a secondary defense against wrongful use of a SIM card. A Personal Unlocking Key (PUK) may be used as a way to unlock your SIM card in the event that you accidentally lock yourself out of your phone using the phone's native security features. PUK codes are separate from phone PINs or Passwords. Call customer support for instructions on how to retrieve your PUK code. Insert your SIM card into an Android phone, which should take you to the PUK screen after booting up, telling you that your SIM card is locked and have ten attempts before it becomes permanently blocked. From there, enter the 8-digit PUK code you've received. If correct, the latter screen will tell you to set up a new PIN code; enter your Your PUK code is tied to the SIM card and the network you're on, so they're the only people who can give it to you. We've listed most mobile networks below - click yours to see how to get your PUK code or the contact info for them. When you've got the code, follow the instructions on the phone. If it doesn't work, contact your mobile network Unlocking mtn and tigo sim with a universal puk? 25% - Universal samsung unlocking i need help? 23% - How do i unlock my call baring service on tigo network on my number 0279002412 how will i be able to deactivate call baring on tigo network and on ite? PUK number. Read time: 29 sec. As a safety feature, your SIM card will automatically lock if the wrong PIN is entered three times. You can unlock it though by entering your PUK (PIN Unblocking Key). How to get your PUK number. Help & Support. How to retrieve your PUK number. SMS 'VPP' to 31050 from the cellphone number you need your PUK for.Dial *135# Select 'Services' Select 'PUK Number'. 1. Get the PUK code from the SIM card packaging The PUK code is printed on the plastic card holding the SIM. The PUK code might be hidden under a. JbU6.