ICCID, IMSI and sim serial number explained
What are the ICCID, IMSI and SIM serial numbers?
The ICCID, IMSI and SIM serial numbers are important identifiers for your SIM cards and mobile connections. You may not need to know what they need in any great detail, but it’s useful to understand what they are and how they are used.
And if you’re wondering, the SIM is the Subscriber Identity Module.
What does ICCID mean?
So what is the ICCID?
The ICCID is, in fact, the SIM serial number. It’s a unique 19 or 20 digit number that’s usually printed on the plastic card that holds the SIM. The long sequence of numbers can be broken up to tell you more about the card.
The first two digits identify the industry sector. For telecommunications, whether it’s a standard mobile SIM or an IoT SIM card, this code is 89. The next 2 or 3 digits reflect the country of issue, for the UK this number is 44.
The following digits identify the mobile network code, sometimes referred to as the MNC. This is a number between one and four digits in length and it identifies the network that issued your SIM card.
The rest of the digits on the SIM card are a unique identifier of that particular card.
These are followed by a checksum digit calculated from the preceding digits, using the Luhn algorithm.
Why do I need to know the ICCID?
What about the IMSI?
What are multi IMSI SIM cards?
When SIM cards were first introduced there was only one IMSI associated with each physical card. Back then it was envisaged that if you were going to another country or using a different phone, you would move your SIM card between devices. Remember back in the early days of cellular, mobile phones were big and heavy and often installed in your car!
Today many SIM cards used for IoT applications often hold multiple IMSIs. This means that the device can switch between different network operators without requiring a different SIM card. This is important for IoT applications that move internationally and require local tariffs for their data charges. Also some applications will need to fail over onto a back up connection in case of a network outage.
Other useful numbers to know
How to find these numbers on your IOT module
Use the command
The command to get your MSISDN only works if it is stored on the SIM which isn’t always the case.