Secure your mobile number and bank account with a SIM card lock

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What is a SIM card lock? A SIM card PIN lock is a simple security measure to protect your SIM card from unlawful access and usage. Simply put, you set and activate a PIN that is required to be entered every time you restart or change your phone. Once your SIM card lock is in place, no-one can use your SIM card without entering your PIN.

Every SIM card issued by a mobile operator or carrier comes with a default PIN, a 4-digit generic number assigned by the operator. For example, many operators use 0000 or 1111 as the default PIN for their SIM cards. We recommend that you contact your mobile network operator for your default PIN.


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As with all passwords, you are required to change your PIN to a more secure number that you can remember and not give it out to anyone else. When you enable a SIM card lock on your mobile number, every time your SIM is in a phone and switched on, your PIN will be required, without which your line is unusable.

Having a SIM lock in place means that there are only 3 attempts to get the PIN right or else the SIM becomes locked and unusable. You will require a PUK, obtainable from your network operator, in order to be able to unlock your SIM for use.


A SIM card lock is a basic but strong security against unauthorised use of your phone. Note that a SIM card lock is different from a phone lock. You can – and should – have both enabled for maximum protection of your mobile number and smartphone.

SIM card lock smartphone security

Why do I need a SIM card lock?

Let’s look at a scenario in which your phone is stolen. Even if the phone is rendered unusable, the thief can still take advantage of your SIM card by putting it into another phone and using it.

If you have bank alerts, investment notifications, and other sensitive information and services attached to your line, all of these information can now be accessed and used by the thief.

If you have a SIM card lock in place, your SIM card is unusable without the PIN you set on it. And should the thief or scammer enter the wrong SIM PIN three times, the SIM card is immediately locked and rendered unusable.


Before you lock your SIM card

As mentioned earlier, in order to enable a SIM lock, you need to change the default SIM PIN. Note, and this is important, that if you forget the PIN you set, you will not be able to use the line in any phone or device until you unlock it with a PUK.

When you contact your mobile operator to unlock your SIM card, they will require that PUK from you.

Where to find your PUK

Check your SIM pack. The PUK is usually included in the documentation in your SIM pack. You can aslo access it from the mobile app of some network operators, so check in there too. When you find it, write it down and hide it away in a secure place for use should you ever need it.

How to lock your SIM card on an Android phone

  1. Go to Settings.
  2. Tap on the More tab.
  3. Tap Security.
  4. Tap Set up SIM card lock.
  5. Tap Lock SIM card
  6. Enter the default SIM PIN (if you haven’t changed it before; if you have, skip this step).
  7. Enter your new PIN
  8. Confirm your new PIN
  9. Tap OK/Okay.

Once you have done this, your personal new PIN is active. Every time you switch on your phone, you will be prompted to enter your PIN before you can access any network related service. If you do not get it right, you will be unable to send/receive telephone calls and SMS, and be unable to use mobile data as well.

PS: The above steps may differ slightly depending on your smartphone’s manufacturer.


Secure your bank account with a SIM card lock

How to lock your SIM card on an iPhone

  1. Go to settings.
  2. Tap on Mobile data
  3. Tap on SIM PIN.
  4. Enter the default PIN
  5. Enter your new PIN.

Don’t forget that a SIM card lock prevents unauthorised access to your mobile line. It is similar to a phone lock, but they are not the same. You should have both a phone lock and a SIM card lock enabled for maximum protection.

Note: for best security and protection, make sure that your phone lock PIN/password is different from your SIM card lock PIN. Don’t use the same PIN for both.

If in doubt about any information or process to secure your mobile number, contact your network operator for assistance. All the best.

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