All network operators in Nigeria have been directed to update their subscriber records so their National Identification Numbers (NINs) are captured.
Read more at https://ncc.gov.ng/media-centre/news-headlines/928-press-statement-implementation-of-new-sim-registration-rules
Here are some useful tips on linking your NIN to your SIM registration records.

Forgotten your NIN?

You can dial *346# on your phone to retrieve your NIN.
Alternatively, you can visit any NIMC office close to you.

Link your NIN to your Mobile Numbers using the NIMC Mobile ID App

Learn how to obtain the app at https://nimc.gov.ng/mobile-digital-id/

  • Open the app and log in with your security PIN.
  • Tap on ‘My Devices’ button on the bottom right part of your dashboard on the app.
  • Tap on ‘Add Mobile Number’ and input the mobile phone number you wish to link.
  • Next input the OTP sent to that mobile phone number.
  • You can link up to seven (7) mobile phone numbers.

Linking NINs to SIMs with NIMC's Mobile ID App

Link your NIN to your Airtel Mobile Number

Visit https://airtel.com.ng/NIN_information
Or you can dial *996#
You can also visit an Airtel service centre close to you.

Link your NIN to your MTN Mobile Number

Visit https://nin.mtn.ng/
Or you can dial *996#
You can also visit an MTN service centre close to you.

Link your NIN to your Glo Mobile Number

Visit https://www.gloworld.com/ng/nin/
Or you can dial *996#
You can also visit a Glo service centre close to you.

Link your NIN to your 9mobile Number

Visit https://www.9mobile.com.ng/nin
Or you can dial *996#

You can visit a 9mobile service centre close to you.