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What is an ICCID number and is it important?

Caburne Telecom IoT SIM
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An ICCID number (Integrated Circuit Card Identifier) is a unique number that is used to identify your SIM card.

It’s usually printed on the back of the SIM card and can also often be read from a device’s settings menu by inserting the SIM card into a mobile phone.

Your ICCID number helps your service provider accurately identify which account you use, as well as helping you keep track of your device’s activity.

As such, it is an important part of using your IoT device and ensuring that all of its associated services remain secure.

Many people often confuse the terms ICCID and IMSI when it comes to mobile technology, but they actually serve different functions. The ICCID (Integrated Circuit Card Identifier) and IMSI (International Mobile Subscriber Identity) are important identifiers with unique functions and information.

1. ICCID: The ICCID is a distinctive serial number that distinguishes the SIM card. It is utilised by network providers to recognise a physical SIM card.

2. IMSI: The IMSI is a unique identifier linked with all mobile networks. It is stored as a field in the SIM card within the device and is transmitted by the device to the network. Its purpose is to identify the user of a mobile network. The IMSI consists of three components: the Mobile Country Code (MCC), the Mobile Network Code (MNC), and the Mobile Subscriber Identification Number (MSIN).

In essence, the ICCID is for SIM card identification and the IMSI is for network user identification.

In this blog post, we will explore the format of ICCID numbers, how to find an ICCID number and how to identify if a SIM is used for a purpose within the Internet of Things (IoT).

Why does an ICCID SIM Card number matter for cellular IoT

An ICCID number is an important part of using cellular IoT devices, as it determines what mobile network operators and cellular networks your device can access and the level of access this device has to that specific network.

Additionally, it can be used to authenticate the connection between the local network operator, the roaming mobile network provider and your device in order to activate services such as temporary or permanent roaming and IoT data or voice services.

An ICCID number also helps the network operator to accurately identify which account is associated with a device, both for billing purposes and in case of theft or loss. Thus, an ICCID number plays an important role in ensuring that cellular IoT devices remain secure and connected at all times.

These numbers are issued by the SIM card manufacturer for MNO/MVNOs and must be registered with the network operator in order to be able to use them.

Structure of an ICCID number

When looking at an IoT SIM card, the first two digits of the ICCID number will always be 89. These digits are a code that identifies the telecommunications industry and distinguishes the device from other chip cards.

The following two or three digit code is the country code. This is determined by the International Telephony Union (ITU). This code, however, is different to that of the mobile country codes (MCCs) used in IMSIs.

The SIM’s home network is represented in the next one to four digits of the ICCID. This is called the mobile network code (MNC) and it identifies the mobile network that issued the SIM card, with each provider and partner company having a unique code.

The remaining digits of the ICCID following the MNC are totally unique to each SIM card to differentiate it from any other SIM hardware. This is called the Individual Account Identification Number (IAIN).

The last digit of the ICCID is the checksum, which is used to validate the integrity of the ICCID number after transmission and is calculated using the Luhn algorithm.

How to find a SIM’s ICCID number

A SIM card’s ICCID number is usually found on the back of the SIM card or on the packaging it came in.

The number can also be found within some devices’ interfaces. For example, on mobile phone devices, the ICCID can also be found directly in the device settings.

Differences between ICCID, IMSI and IMEI

Considering their similar spelling, it’s common for some people to confuse an ICCID number with that of an IMSI number or IMEI number. However, it’s important to note that these are three different numbers.


Although we have already dissected what an ICCID number is, it’s important to reiterate that an ICCID number is a unique 18 to 22 digit ID used to identify your SIM card.

The structure of an ICCID is:

  • Major industry identifier (MII): First two numbers, always 89 for telecom purposes
  • Mobile Country Code (MCC): The following one to three numbers
  • Mobile Network Code (MNC): The next one to four digits.
  • Individual Account Identification Number (IAIN): The remaining digits.
  • Checksum: The very last digit of the ICCID


An IMSI (Multiple International Mobile Subscriber Identity) is a unique identifier that is used by MNOs and MVNOs to identify SIM cards.

The IMSI identifies the home network of the device and can be obtained from any mobile service provider.

The structure of an IMSI is:

  • MCC: The first three digits found on the SIM card, which represent the user’s home network.
  • MNC: The following two to three digits are the mobile network code.
  • Line of service or subscriber (MSIN): The remaining digits.


An IMEI (International Mobile Equipment Identity) is a unique 15 or 16 digit code that identifies mobile devices and modems.

This number is usually printed on an IoT device and is a number that’s checked against the global IMEI database.

The structure of an IMEI is as follows:

  • Reporting body: The first two digits of the IMEI.
  • Type allocation code (TAC): The next six digits are the actual type allocation code of the device.
  • Device distinctive ID number: The next five digits are unique to the device.
  • Check digit: The last digit of the IMEI.

How does embedded SIM technology affect ICCIDs?

In recent years, embedded SIM technology has become increasingly popular in the IoT industry.

Embedded SIMs (or eSIMs) are a type of SIM card technology that is embedded directly into the device and cannot be removed or changed.

This means that it is no longer mandatory to use traditional, removable plastic SIMs, if an IoT device can use eSIMs instead which are embedded on the PCB,s or modem boards.

eSIMs also have a unique set of ICCIDS that allows them to connect to multiple networks and switch between them.

An eUICC eSIM or eUICC plastic SIM [eUICC: embedded Universal Integrated Circuit Card] can also use GSMA-approved software and architectures which allows the SIM to be provisioned remotely post-manufacture without the need to physically remove and exchange the SIM card.

eUICCs SIM cards use a different method of using ICCIDs. They use an eUICCID (EID) which is a unique ICCID to identify the physical SIM or eSIM card. 

The ICCID for an eUICC SIM card, however, is the current active profile on the SIM card. This is important as eUICC SIM cards can hold multiple operator profiles, only one of which can be active at any one time. Others are being used for certain countries as they are more cost-effective, provide permanent roaming, or as a backup safeguard.

Discover more about the difference between eSIM and eUICC and the differences between an eSIM and an integrated SIM (iSIM) by reading our other articles.

Endless IoT connectivity solutions

Thank you for reading our post about what an ICCID number is. We hope you learnt something new.

Caburn Telecom is an industry leader in IoT solutions and provides a range of global, reliable and secure IoT connectivity solutions. Our team is made up of experienced professionals who are dedicated to providing the best service for you.

With physical and eSIM solutions available, we’re prepared to meet the needs of your IoT operation. Talk to our team today and start exploring what Caburn Telecom can do for you.