How to lock your SIM card on Android and iPhone phones

Phone theft is bad enough, but criminals are now targeting SIM cards to access sensitive information, including bank details. Recently, there has been a rise in fraud cases linked to stolen SIMs, leading to unauthorised fund withdrawals and identity theft.

One of the simplest yet most effective ways to protect yourself is by enabling a SIM card PIN lock. This security feature ensures that even if your phone is stolen, your SIM card remains inaccessible without the correct PIN.

Why you should lock your SIM card

Prevents SIM swap fraud – Once fraudsters have access to your phone, they immediately swap your SIMs into other devices to gain access to OTPs (one-time passwords) for online transactions. This will grant them access to your bank accounts and other personal information.

Protects bank and social media accounts – Many financial services and social media platforms use your phone number for authentication. A locked SIM prevents unauthorised access to your bank apps and social media accounts.

Stop unauthorised calls and SMS – Criminals may use your SIM to make expensive calls, send scam messages, or commit fraud. A locked SIM will prevent them from doing all these.

How to enable SIM card PIN lock

For android users:

1. Open settings

2. Navigate to security & privacy (or biometrics & security on some devices)

3. Select more security settings near the bottom of the page

4. Select SIM card lock

5. Tap set up SIM card lock

6. Enable lock SIM card

7. Enter your default SIM PIN (see default PINs below)

8. Change the default PIN to a new, secure one

For iPhone users:

1. Open settings

2. Go to cellular (or mobile service on some iOS versions)

3. Tap SIM PIN

4. Enable SIM PIN

5. Enter your default SIM PIN

6. Change the default PIN to a more secure one

To confirm if it worked, transfer your SIM to another device or reboot your mobile phone. When you do this, whether an iPhone or Android, you can’t use it until it’s unlocked. Here’s what you see.

Default SIM PINs for Nigerian networks

If you haven’t set a SIM PIN before, your network provider assigns a default PIN:

Airtel: 1111

MTN: 0000

Glo: 0000

9Mobile: 0000

If unsure, contact your mobile provider before proceeding.

What happens if you enter the wrong SIM PIN?

Be careful when entering your SIM PIN. After three incorrect attempts, your SIM will be locked, and you’ll need a PUK (Personal Unblocking Key) to regain access.

How to retrieve your PUK code

Check the SIM pack (PUK is usually printed on it)

Call your network provider’s customer care

Use the network provider’s app or website (if available)

More security tips

Choose a strong PIN that isn’t easy to guess. Avoid 1234 or your birth year.

Do not share your SIM PIN with anyone.

Regularly update your SIM PIN for added security.

By locking your SIM card, you add a strong layer of security to your personal and financial information. This simple step could save you from losing money or having your identity stolen.