> For the complete documentation index, see [llms.txt](https://sim-cards.learn-telecom.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sim-cards.learn-telecom.com/gsm-identifiers/imsi.md).

# IMSI -

The IMSI is a unique identifier that is used to identify the subscriber on the network. It consists of a Mobile Country Code (MCC), Mobile Network Code (MNC), and Mobile Station Identification Number (MSIN). 

The MCC and MNC are used to identify the network operator, while the MSIN is used to identify the subscriber within the network.