What is MSISDN?

MSISDN (Mobile Station International Subscriber Directory Number) is a number uniquely identifying a subscription in a Global System for Mobile Communications (GSM) or a Universal Mobile Telecommunications System (UMTS) mobile phone network. It is stored in the Subscriber Identity Module (SIM) of the phone.

It is used to identify the user and is used for services such as billing, roaming, short message service (SMS), and call forwarding. It also helps operators to identify customers and provide them with the services they need. 

MSISDN is usually a 10 or 11-digit number and is usually printed on the back of the SIM card. MSISDN can also be used to identify the location of the user and the type of network the user is connected to. In some cases, it can even be used to identify the phone manufacturer and model.

How does it work?

MSISDN is used to identify the user’s SIM card and the services provided by the mobile network. When a user makes a call or sends a text, the MSISDN associated with their SIM card is used to identify them and the type of service they are using. The mobile network will then use the MSISDN to connect the user to the appropriate service and bill them accordingly.