Stands for "Integrated Circuit Card Identifier." An ICCID is a unique number assigned to a SIM card used in a mobile phone or another cellular device. It provides a standard way to identify each mobile device connected to a cellular network.
An ICCID is 19 or 20 digits long and contains individual sections of numbers, including a header, ID number, and check digit, calculated using a checksum. The header is 6 or 7 digits long and includes the following information:
- Major industry identifier (MMI) - the first two digits — always 89 for SIM cards
- Country code (CC) - one to three digits — represents USA, England, Japan, etc.
- Issuer Identifier Number (IIN) - two to three digits — represents Verizon, AT&T, T-Mobile, etc.
ICCID vs IMEI
Both the ICCID and IMEI (International Mobile Equipment Identity) are unique IDs for mobile devices. However, the IMEI is attached to the hardware while the ICCID is assigned to a removable SIM card. Therefore a smartphone will always have the same IMEI, but the ICCID will change if the SIM card is replaced.
Cellular providers activate devices based on their ICCID rather than their IMEI. Since each mobile account is linked to an ICCID, it is possible to use the same device on multiple networks by merely swapping out the SIM card.