MSIN
The subscriber part of an IMSI after the MCC and MNC.
Definitions only — a term explained here is not a service we sell.
The mobile subscriber identification number (MSIN) is the part of an IMSI that identifies the subscription inside a network. It follows the three-digit MCC and the two- or three-digit MNC.
Why it matters
The MSIN is the part a network uses to find one subscriber among many. Because the MNC length varies, the boundary between MNC and MSIN is not fixed, and a parser that splits by position will misread some IMSIs.
MCC, MNC and MSIN
- MCC 274
- MNC 01
- MSIN 1234567890
Text description
The example is illustrative. MCC 274 is Iceland; the MNC length depends on the assignment, so the MSIN starts after an MNC of two or three digits. Never parse an IMSI by a fixed character count.
What to check
Keep an MCC-MNC table that records MNC length per network, and validate the split against it. Do not use the MSIN as a public identifier; it is part of the subscription identity and belongs with the IMSI in restricted logs. The IMSI term and the MCC and MNC tools show the full structure.