Your new SIM could be someone else’s old number: Inside Nigeria’s risky SIM recycling system 

Imagine obtaining a new SIM card, and one of the first welcome messages was a debit alert for N500,000. You were surprised that it’s a new SIM that hasn’t been linked to any of your bank accounts. You check the details of the message only to find out the alert is meant for someone else. 

Then you ask in soliloquy, “How come?” “Was the SIM card mistakenly registered to another person at the point of registration?” “Does the SIM card initially belong to someone else?” “Did the telco do a bad cleaning job even if it was a phone number previously used by another person?” 

You ask around only to find out, to your wildest surprise, that this has become a normal occurrence: receiving bank transaction details belonging to someone you don’t know. 

While this has been a recurring experience, the feeling was different for a particular X user, @Olami_deeEbony, who expressed her shock upon experiencing the same drama. 

She bought a new MTN SIM on Friday, only to start receiving transaction alerts belonging to a UBA account. It dawned on her that the phone number must have been previously used by a UBA customer, meaning she had been sold someone’s old line. 

Aside from the user, multiple X users are also in her shoes. Check here, here, and here.

Responding to the post, MTN Nigeria, through its customer support account, explained that “banks are responsible for updating or disconnecting the old number from customer accounts” when a number is reassigned. 

It added that if the previous owner fails to deactivate the phone number from the bank account, alerts may continue until the bank updates its system. 

In addition, MTN elaborated on the recycling system, noting that SIMs are transferred to another user after 360 days of inactivity. 

“In Nigeria, mobile numbers are not permanently owned. The NCC permits all GSM operators to recycle lines after 360 days of no activity (no calls, SMS, data or revenue‑generating events – WhatsApp calls over Wifi do not count too),” it said. 

Also Read: MTN, Airtel, Glo, others must now inform subscribers of data breach within 48 hrs.

The SIM card recycling system

SIM card recycling is a process where a dormant SIM card is deactivated and recycled by a telco and made available to the public. The process occurs after a SIM card has been dormant for a consecutive period of 3 months or more, depending on the policy of the telco.

At a virtual stakeholder meeting in April 2025, NCC Executive Vice Chairman Aminu Maida noted that the Quality-of-Service Business Rules 2024 stressed that a prepaid line without a revenue-generating event for six months must be deactivated. 

For telcos, recycling is purely economical and not a mere ‘technical’ decision. 

In policy, SIMs are owned by the federal government (in this case, the Nigerian Communications Commission (NCC)) and cannot be transferred or completely owned by a telco. 

Section 70 of the NCC Act has made provisions for ‘Development of a new numbering plan for Nigeria.’ Therein, telcos are obligated to pay a sum (numbering plan fees) to maintain their allocated numbers. Such fees are stipulated by the NCC at regular intervals, and are subject to review as the Commission may deem appropriate.

For an operator, it is seen as non-economical to pay for a SIM card that is inactive and not generating income. This explains the inactivity period threshold and recycling policy.

In his explanation, Chairman of the Association of Licensed Telecom Operators of Nigeria (ALTON), Gbenga Adebayo, noted that subscribers do not have ownership rights to SIMs in their possession because telcos pay procurement and recurring costs for each registered subscriber.

Adebayo clarified that SIM cards are recycled to prevent number exhaustion while reducing the cost of generating and maintaining them. He added that “SIM cards are reassigned to reduce the dormant subscribers, as telcos are profit-oriented organisations.”

The gaps

However, serious complications emerge when a recycled SIM Card is still linked to a previous user’s sensitive data, such as a bank account. 

While Section 28 of the NCC’s draft business states that all recycled SIMs must be thoroughly cleaned of any NIN attached to allow a new user to link their own NIN, the reality still shows that many recycled phone numbers are not properly purged before being reassigned. 

As a phone number is still tied to the user’s bank accounts, this means that his/her Bank Verification Numbers (BVNs) and National Identity Numbers (NINs) are still linked to such. Reassigning them can expose people to financial loss.

It could also expose them to identity theft, which is another red flag. What the ‘weak’ recycling system does in reality is that a new user assumes the identity of the previous SIM card owner. And this is a loophole fraudsters leverage on by posing as the previous owner to defraud people. 

Also Read: What do your phone signal bars mean? A simple explanation.

Going forward 

Experts have advised the NCC and telcos to find a way to notify users when their numbers are at risk of being deactivated and when the deactivation comes into effect.

Subscribers also need more orientation about deactivating their previous phone numbers from their bank accounts. This prevents a case where new users inherit access to financial messages and other sensitive data.

Experts also encourage telcos to enlighten their subscribers on SIM card deactivation, maintenance, and reactivation. This is quite necessary for those who are travelling out of the country with intentions to return after a certain period.

The post Your new SIM could be someone else’s old number: Inside Nigeria’s risky SIM recycling system  first appeared on Technext.