With the rising cases of SIM swap fraud, data theft, and unauthorized browsing, many MTN users in Nigeria are asking an important question: “Which code can I use to lock my MTN mobile data?”
If you’re worried about someone using your MTN data without permission, this guide explains what is possible, what is not, and the best way to secure your MTN SIM and mobile data in 2026.
Is There a Code to Lock MTN Mobile Data?
Short answer: NO.
As of 2026, MTN Nigeria does not provide any USSD code to directly lock mobile data or browsing on your SIM card. However, that does not mean your data is left unprotected.
The safest and officially supported method is to activate a SIM Card Lock (SIM PIN) on your phone. This prevents anyone from using your MTN SIM including your mobile data without your permission.
Why You Should Lock Your MTN SIM Card
Activating a SIM lock helps you:
- Prevent unauthorized data usage
- Protect against SIM swap fraud
- Stop hackers from accessing your MTN line
- Secure your calls, SMS, and internet subscription
- Protect banking, WhatsApp, and OTP messages linked to your line
Once your SIM is locked, your MTN data cannot be used on another phone without the PIN.
How to Lock MTN Mobile Data Using SIM Card Lock
For Android Users
Follow these simple steps:
1. Open Settings on your phone
2. Scroll down and tap Security or Privacy & Security
3. Select SIM Card Lock
4. Turn ON Lock SIM Card
5. Enter the default MTN SIM PIN (usually 0000 or 1234)
6. Tap Change SIM PIN
7. Set a new unique 4-digit PIN
8. Confirm the PIN
9. Restart your phone to test it
After this, your MTN SIM will request a PIN whenever the phone is restarted or the SIM is inserted into another device.
For iPhone (iOS) Users
1. Go to Settings
2. Tap Mobile Data or Cellular
3. Select SIM PIN
4. Turn ON SIM PIN
5. Enter the default SIM PIN
6. Change it to a new 4-digit PIN
Once enabled, your iPhone will request the SIM PIN anytime the phone is powered on or the SIM is reinserted.
What If My MTN SIM Is Blocked (PUK Code Issue)?
If you enter the wrong SIM PIN three times, your SIM will be blocked and request a PUK (Personal Unblocking Key).
How to Fix It:
- Check your original SIM card pack for the PUK
- Dial 180 to contact MTN Customer Care
- Visit the nearest MTN Service Center with a valid ID
Do NOT guess the PUK. Multiple wrong attempts can permanently damage the SIM.
Frequently Asked Questions (FAQs)
Can I lock MTN data using a USSD code?
No. MTN does not offer any USSD code to lock mobile data.
Does SIM lock stop data sharing?
Yes. Once the SIM is locked, it cannot access data on another device without the PIN.
Will SIM lock affect my internet speed?
No. It only improves security, not performance.
Is SIM lock free?
Yes. It is completely free and done from your phone settings.
Conclusion
There is no direct MTN code to lock mobile data in Nigeria. However, enabling a SIM card lock (SIM PIN) is the most effective and secure method to protect your MTN data from unauthorized use.
Whether you use Android or iPhone, activating SIM lock adds an extra layer of protection against hackers, SIM theft, and data misuse.
If data security matters to you , SIM lock is a must.