How to lock your SIM on Android

What is a SIM card lock?

A SIM card lock is a layer of security, in addition to the screen lock, that prevents carrier services from being used unless the SIM is unlocked. This is different from a cellphone being carrier-locked, which means a phone can only use SIM cards from a certain carrier. The lock is a PIN, which must be entered each time the phone is turned on, even if the SIM is moved to a different phone. This extra layer of security prevents someone from using your SIM on any phone without knowing your SIM unlock PIN.

www.expedia.com/cheap_flights/WashingtonFlights to Washington Airport - Last Minute Flight Deals

Ad

The reason for activating a SIM card lock is due to SIM phishing. Scammers use SIM phishing, also known as SIM swapping, to gain access to your SIM card and control your mobile device. For this, they collect as much personal information as possible from your social media and other accounts. Then, they trick your carrier and its customer service executive into believing you contacted them and asked them to transfer your number to a spare SIM card they (the scammer) own. A SIM card lock, however, prevents the scammer from gaining access to the SIM and the carrier's network through it.

How to activate and modify a SIM card lock on an Android phone

Setting up a SIM card lock requires you to enter the default passcode set by your operator. The default SIM PIN is often on the packaging that comes with your phone. Make sure you know the default PIN before setting up the SIM card lock, as you will be locked out of your SIM after a few incorrect attempts.

1. Launch the Settings app.
2. Scroll down and select Security & Privacy.
3. Select More security settings near the bottom of the page.
   

   A screenshot of the Settings app on a Google Pixel phone with a red arrow pointing to the Security & Privacy option© Provided by Android Police

   

   Security & Privacy settings on a Google Pixel phone with a red arrow pointing to the More security settings option© Provided by Android Police
4. Tap SIM card lock.
5. Turn on the Lock SIM card toggle.
6. You may be prompted to enter the default PIN.
   

   More security settings on a Pixel phone with a red box around the SIM card lock option© Provided by Android Police

   

   SIM card lock settings on a Google Pixel phone with a red arrow pointing to the Lock SIM card toggle© Provided by Android Police
7. After it's turned on, tap Change SIM PIN to change your PIN.
   

   SIM card lock settings on a Pixel phone with a red box around the Change SIM PIN option© Provided by Android Police
8. Enter your old PIN, then enter your new PIN, and tap OK. Be careful while entering your old PIN. Entering the wrong PIN three times blocks your SIM and requires you to get a new SIM.
   
   

   

   The Lock SIM card dialog box prompting you to enter your current SIM PIN on a Pixel phone with a red arrow pointing to the entry line© Provided by Android Police

   

   The SIM PIN dialog box prompting you to enter your new SIM PIN on a Pixel phone with a red arrow pointing to the entry line© Provided by Android Police

You can test if this worked by moving your SIM to a different mobile phone. When the SIM is transferred to a different phone, whether an iPhone or Android, you can't use it until it's unlocked. Here's what you see when you insert your locked SIM into another iPhone or Android device:

A screen prompting you to enter the SIM PIN on a Pixel phone© Provided by Android Police

How to activate and modify a SIM card lock on a Samsung phone

Samsung phones have the One UI Android skin, which looks and functions slightly different from stock Android. Follow the steps below to set up a SIM card lock on your Samsung Galaxy phone.

1. Open the Settings app on your Samsung phone.
2. Scroll down and tap Security and privacy.
3. Select Other security settings.
   

   The Samsung Settings app with a red arrow pointing to the Security and privacy option© Provided by Android Police

   

   Security and privacy settings on a Samsung phone with a red arrow pointing to the Other security settings option© Provided by Android Police
4. Tap Set up SIM card lock.
5. Turn on the Lock SIM card toggle.
   

   Other security settings on a Samsung phone with a red arrow pointing to the Set up SIM card lock option© Provided by Android Police

   

   Set up SIM card lock settings on a Samsung phone© Provided by Android Police
6. Enter your current SIM card PIN and tap OK.
7. Select Change SIM card PIN and enter a new passcode to protect your SIM.
   
   

   

   The Lock SIM card dialog box prompting you to enter your current SIM PIN on a Samsung phone© Provided by Android Police

   

   Set up SIM card lock settings on a Samsung phone with a red arrow pointing to the Change SIM card PIN option© Provided by Android Police

What happens if I am locked out of my SIM?

If you accidentally get locked out due to entering an incorrect PIN three times, your phone prompts you to enter a Personal Unlock Key (PUK), an eight-digit number. This number is located on the packaging your SIM card came in. If you don't have the box, contact your carrier and verify yourself to get the PUK from them. Store your new SIM PIN in one of the top password managers on Android so that you never lose it.

www.expedia.comCheap Flights to DCA Airport

Ad

What if you have an eSIM?

You can still activate a SIM card lock if you have an eSIM. Even if you have a SIM card lock on a physical SIM, anyone can remove it and work on unlocking the SIM on another device. An eSIM is more secure because it can't be removed from your phone, so it's harder to unlock it without the SIM PIN. Follow the steps listed above to activate a SIM lock on an eSIM.