Numbers • Last Updated 11/8/2023

What is an ICCID number, and what is its purpose?

Discover how a SIM card’s ICCID number influences device registration, security, and management.


By Emily Bowen

ICCID number Telnyx green logo

Mobile connectivity issues? Security vulnerabilities? Registration difficulties? The ICCID number might be the root cause. Understanding its role can mean the difference between smooth device deployment and costly mishaps.

To ensure seamless operations and robust security in mobile communications, understanding the intricacies of ICCID is crucial. Join us as we explore the role of the ICCID and other mobile identifiers.

What is an ICCID number?

An ICCID (Integrated Circuit Card Identifier) is the unique serial number of every SIM card. Beyond serving as an identifier, it plays a pivotal role in network registration, security protocols, and user-specific services. A misstep or oversight related to the ICCID can lead to a host of issues.

ICCID number location

You'll often find the ICCID printed on the SIM card, and it's also accessible in the device's settings. This number has a specific structure that offers insights about the card, from its origin to its capabilities.

Every ICCID follows a specific format, with each segment providing insights about the SIM card:

ICCID number breakdown

Industry code

The major industry identifier (MII) is the first segment of the ICCID. This segment is typically set to 89—which is reserved for the telecommunications sector—on SIM cards. The code ensures any system or network reading the ICCID immediately recognizes it as belonging to a telecommunications device. It's similar to a prefix in phone numbers that tells you which country or region the number belongs to.

Country code

The country code in the ICCID provides geographical context to the SIM card's origin. It's a standardized set of numbers that corresponds to individual countries. For instance, 310 and 311 are the codes for the U.S. So, if a SIM card's ICCID contains 310 or 311, it was issued in the United States. This segment is crucial for roaming services, as it helps foreign networks identify the home country of a roaming device and apply appropriate charges or restrictions.

Issuer identifier

Every mobile network operator globally has a unique issuer identifier. This segment of the ICCID ensures the SIM card is recognized and treated appropriately on its home network. For instance, if you're using a Telnyx SIM card, this segment would contain Telnyx's unique identifier, 210. It helps in tasks like billing, network registration, and ensuring the correct services and privileges are granted to the user.

Unique SIM identifier

This segment is the unique identifier for the individual SIM card. Given the millions of SIM cards in circulation globally, this segment ensures each one can be distinctly identified. It's similar to having a unique ID number or Social Security Number for individuals. This number is particularly important for mobile operators to manage their subscribers, track activations, and handle customer service inquiries.


The checksum is a form of error checking. It's derived mathematically from the other numbers in the ICCID. When systems read the ICCID, they can perform a calculation on the other digits and check it against the checksum. If the numbers don't match, it indicates there might have been an error in reading or transmitting the ICCID or that the ICCID might have been tampered with. The checksum ensures the integrity and authenticity of the ICCID.

What is the purpose of an ICCID?

In mobile communications, an ICCID acts as a gatekeeper and facilitator for various essential services and interactions.

Network registration

Whenever a mobile device is powered on or enters a new coverage area, it must be registered with the local mobile network to receive services. The ICCID is one of the primary identifiers the network checks to authenticate and authorize the device. This registration process ensures the SIM card (and, by extension, the user) has the necessary permissions and subscriptions to access the network's services.

Security protocols

Security is paramount in mobile communications because any breach or vulnerability can lead to unauthorized access, data theft, and potential misuse of personal and sensitive information. The ICCID plays a role in the encryption processes that secure communications between the mobile device and the network. When a device connects to a network, the ICCID and other identifiers are used to establish a secure encrypted channel that protects voice calls, text messages, and data usage from eavesdropping or tampering.

User management and device activation

Managing millions of subscribers is complex for mobile operators. The ICCID provides a consistent, unique identifier for each SIM card, making it easier for operators to track device activations, manage user subscriptions, and handle billing. When a new SIM card is activated, the ICCID is logged and associated with the user's account, ensuring accurate service provisioning and billing.

Roaming services

Roaming allows users to use mobile devices outside their home network's coverage area. When a user travels internationally and turns on their device, the ICCID is one of the identifiers foreign networks use to determine the device's home network. This information is used to establish roaming agreements, ensuring the user can make calls, send texts, and use data while abroad.

To further understand the ICCID's significance, it's essential to differentiate it from other mobile identifiers.

ICCID vs. other SIM card identifiers

The ICCID is one of several key identifiers used in mobile devices, each with its specific function. You’ll also see two other identifiers:


The International Mobile Subscriber Identity (IMSI) is another crucial identifier stored on the SIM card. Unlike the ICCID, which identifies the physical SIM card, the IMSI identifies the user or subscriber of the mobile service. It's used during network registration and authentication processes. The IMSI is essential for networks to provide services tailored to individual users, such as personalized call plans or data packages.


The International Mobile Equipment Identity (IMEI) is a unique identifier for every mobile device, such as smartphones and tablets. While the ICCID and IMSI are tied to the SIM card and, by extension, the user, the IMEI is tied to the device itself. It's used to track the device, for warranty purposes, and in cases of theft. If a device is reported stolen, networks can blacklist the IMEI, preventing the device from accessing any mobile network, regardless of the SIM card inserted.

The ICCID, IMSI, and IMEI are foundational to the operation of mobile networks, ensuring users can communicate securely, efficiently, and seamlessly, whether at home or abroad.

How to access your ICCID

Knowing how to locate your ICCID can be beneficial, especially when troubleshooting or setting up new devices. Here's how you can find it on various platforms:

Android smartphones

  • Open the 'Settings' app on your device.
  • Scroll down and select 'About Phone' or 'About Device.'
  • Look for an option that says 'SIM Status' or 'Status.'
  • Within this menu, you should find the ICCID or 'SIM Serial Number.'


  • Go to 'Settings.'
  • Navigate to 'General.'
  • Select 'About.'
  • Scroll down to find the ICCID.

Physical SIM

If you remove the SIM card from your device, you'll often find the ICCID (typically a 19- or 20-digit number) printed directly on the SIM card.

The future of ICCID is intrinsically tied to the evolution of mobile communication technologies and the broader shifts in the telecommunications landscape. Here are some predictions and comments on the trends surrounding ICCID:

Integration with eSIM technology

The rise of eSIM technology doesn't signal the end for ICCID. Instead, the ICCID will continue to serve as the unique identifier for these digital SIM profiles. As more devices adopt eSIM technology, the importance of ICCID in managing these profiles and ensuring secure network access will grow.

IoT and the multiplication of devices

The Internet of Things (IoT) is leading to an explosion in the number of connected devices. From smart home appliances to industrial sensors, each of these devices may require a unique identifier, especially if they connect via cellular networks. The ICCID could play a crucial role in managing this vast array of devices, ensuring each has a unique identity on the network.

Enhanced security protocols

With increasing cybersecurity and data privacy concerns, the ICCID's role in security protocols might be enhanced. It could be integrated into more advanced encryption or multi-factor authentication processes to ensure secure communication.

Dynamic ICCID allocation

In the future, we might see dynamic allocation of ICCIDs, especially with eSIM technology. Instead of a fixed ICCID, devices could be assigned temporary ICCIDs based on their network or region, enhancing flexibility and security.

Integration with blockchain and distributed ledgers

There's growing interest in using blockchain technology for secure, transparent, and tamper-proof record-keeping in various industries. ICCIDs could be integrated into blockchain systems to ensure a transparent record of device activations, usage, and network interactions.

While the form factors of SIM cards and the technologies surrounding them might change, the ICCID's foundational role as a unique identifier in mobile communications is set to remain crucial. Its adaptability and integration into emerging technologies will ensure its relevance in the ever-evolving telecommunications landscape.

Elevate your SIM card management with Telnyx

Effectively managing a vast array of SIM cards and their associated ICCIDs is no small feat, especially when juggling millions of subscribers. The intricacies of the ICCID number highlight the precision and complexity inherent in today's telecommunications landscape. While understanding the ICCID is crucial, it's just one piece of the puzzle.

Telnyx, with its cutting-edge eSIM technology and robust IoT SIM card offerings, is poised to be that partner. We recognize the challenges businesses face and offer solutions tailored to streamline SIM card management. Our platform empowers developers, engineering leaders, and technical operation managers, ensuring that your devices remain connected, secure, and efficient, all while simplifying the management process.

Whether you're diving into a new IoT project or refining your existing mobile communications infrastructure, Telnyx stands ready to assist. Partner with us to harness the full potential of SIM cards, eSIMs, and ICCIDs.

Talk to a Telnyx expert today to explore our IoT SIM card offerings and discover how we can help your business thrive in IoT.

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