The various mobile connectivity operators usually called MNO’s use certain identification traits like ICCID numbers. This helps in determining which network shall a subscriber be attached to. The ICCID number is associated with the SIM card, thereby, sometimes known as the SIM card number. In this blog, we will learn out ways of how to find the ICCID number of your SIM.

Brief Overview — the ICCID Number

The ICCID of your SIM card determines which cellular networks your device can access and its access level. So if you are making mobile devices for the Internet of Things (IoT); it’s quite important to understand what an ICCID is and how it works. In this article, we will go into that :

  • What each digit of the ICCID means.
  • How to find your SIM ‘s ICCID
  • How MNOs use the ICCID of your SIM
  • ICCID vs. IMSI vs. IMEI

The ICCID number of a SIM card is a single string of 18-22 digits; but each ICCID consists of four groups of digits. Let us take the number 8991458910459304236E as an example.


  • In each ICCID number, the first two digits are always 89. This is an industry code indicating that the product is for telecommunications networks.
  • Thereafter, the six following digits are the country codes, determined by ITU(International Telecommunication Union). Here, we have 91, the country code for India.
  • Following the country code is the mobile network code (MNC); around 4digits string associated with the mobile network operator (MNO) that issued the SIM card. This code essentially represents the home network of your SIM card.
  • The last set of digits is completely unique to each SIM. No other SIM in the world will have this exact combination.
  • It allows you to view a specific SIM in a SIM manager, activate or cancel a service; or interact with your connection provider’s customer service. In our example, this combination of numbers is 10459304236E.

How to find your ICCID Number

Since you need the ICCID number to manage a specific SIM card, it’s important to know how to find it. This number is usually seen on the packaging of your SIM. But, what if that is not possible. Then, what to do we do now.

You can insert the SIM card into a device and then use the device to retrieve the ICCID number. On a mobile phone, you can find the ICCID in your settings menu.

How do Mobile Network Operators use ICCID

After you insert a SIM card into a device that uses a cellular connection, it searches for available cellular networks; and then uses the ICCID number and IMSI to determine if the device has access rights to the network.

  • When a device connects to any network, that network sends an authentication request to the device’s home network.
  • The home network sends something that basically amounts to a puzzle that only the device can solve.
  • The network generates a random number and tells it to the device.
  • It then uses an algorithm and a shared secret key to generate a new number based on the random number.
  • If the device generates the same number; it proves that it has the same secret key and is therefore authorized to use the network.
  • If the SIM card does not have the correct key to access the network; the device can only use the network to call emergency services.

IMEI vs IMSI Numbers

In addition to ICCID, there are two other identifiers for cellular networks that you should be aware of. These are the IMSI and IMEI numbers. We have learnt a bit about ICCID Numbers, now lets see what IMSI and IMEI numbers are. A thing to note here is that, the ICCID number identifies SIM card; while the IMSI identifies the subscriber company and the IMEI number is specific to a mobile terminal.

International Mobile Equipment Identification Number (IMEI)

The International Mobile Station Equipment Identity, or IMEI, is a unique 15-digit serial number that uniquely identifies each mobile terminal. It usually consists of four parts:

  • The first two digits indicate the reporting agency identifier; which is the TAC of the GSMA approval group.
  • Thereafter, the following 6digits are Type Allocation Codes.
  • There again, the next 6digits are unique identification numbers for each mobile terminal.
  • The terminal digit facilitates to prevent errors in mobile terminal’s repositories. Thus, it is known as the check digit, as it check for errors and prevents them from occuring and recurring.

Here’s a quality read on how to change your IMEI number?

International Mobile Subscriber Identity (IMSI)

IMSI stands for “International Mobile Subscriber Identity”. It is the unique identification number of a mobile subscriber. Like an ICCID, an IMSI is also stored on the SIM card. Most SIM cards store only a single IMSI; which is associated with a list of networks to which the subscriber has access.

Some SIM’s have multiple IMSI as they can store multiple identities. This thus allows SIM to change identities to access more networks and select the network with the best coverage. An IMSI is not the same as a phone number. The IMSI number has up to 15 digits and consists of three parts:

  • Digits 1-3 represent the country code. This helps in identifying the home country of the operator who issued the SIM card. Say, for example, the IMSI of European countries always starts with the digit 2.
  • Also, the next 2-3 digits are Network Codes, which stands for the network in which the user is active.
  • All subsequent digits are assigned specifically to the user, and no two users have the same IMSI number.


Hope that you have found this a very knowledgeable experience reading through the whole text. I am sure, that now you will be successfully dealing with knowing your ICCID numbers. In this post, we also see how to find ICCID Number and also how do different MNO’s use these ICCID Numbers. We have also seen a comparative study of ICCID, IMSI and IMEI numbers. Hoping that this post thus, helps you in your endeavors. It is intended for knowledge purspose only. Until next time, good bye. See-ya !! 🙂

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