How and why to activate SIM lock on your Android

Prevent malicious SIM card use by adding an extra layer of security

A SIM card allows you to have conversations and send text messages all over the world. It’s also a gateway to your bank account, social media, and other personal information. If your phone is stolen, you can block your SIM card quickly by contacting your operator. However, you may realize this too late, once the damage has been done. You can add an extra layer of security to protect your SIM card on Android if your device has a SIM card slot.


The SIM card lock feature has been on top Android phones for years. After activating it, you will enter your four-digit SIM card passcode after reboot or when transferring to another phone.

How to set up a SIM card lock on Android

Setting up a SIM card lock requires you to enter the default passcode set by your carrier. In most cases, the passcode is either 0000, 1111, or 1234. To prevent your SIM card from being locked after three attempts, look for it on the plastic card containing your SIM card. Be very careful, because three unsuccessful attempts block your SIM card. Then you will need to contact your carrier to unblock it.

  1. Go to Settings > Security > More security settings.
  2. Faucet SIM card lock.

  3. To light up Lock SIM card and enter the Default PIN if you are activating it for the first time.

  4. Once activated, press Change SIM card PIN to change the Default PIN.

  5. Enter your old PINenter your new pinand touch OKAY. Be very careful when entering your old PIN. Entering the wrong PIN code three times blocks your SIM card.

  6. To test functionality, reboot your phone.

When the SIM card is transferred to another phone, be it iPhone or Android, you cannot use it until it is unlocked. Here’s what you see when you insert your locked SIM card into another iPhone or Android device.

The process of activating SIM lock may differ from phone to phone. Whatever your phone, use the search box in the Settings app to search SIM lock and activate it.

Other ways to protect your SIM card

Scammers use SIM phishing, also known as SIM swapping, to gain access to your SIM card and take control of your phone. For this, spammers collect as much of your personal information as possible from your social networks and other online accounts. Then they make your carrier and their customer manager think that you contacted them and asked them to transfer your number to a spare SIM card they (the scammer) have. So if you have personal information made public on social media websites, delete it. Although these attacks are rare, prevention is better than cure.

There are other ways to protect yourself and your phone. If you’re getting too many unwanted calls, learn how to block unwanted calls on Android. And learn how to spot and report phishing emails to keep you and your community safe.