What is an ICCID number and why is it critical for SIM management?

Table of Contents 

• What you’ll learn from this article
• What do the numbers in an ICCID mean?
• Can ICCID numbers be recycled or reused?
• How to find the ICCID number
• ICCID vs. IMSI vs. IMEI
• Troubleshooting an ICCID number
• Optimizing IoT operations with effective SIM management  

What you’ll learn from this article

Every SIM card in an IoT device has an ICCID (Integrated Circuit Card Identification)—a number that acts as its unique identifier in the mobile network. It’s how your devices stay connected and traceable across global networks.

Today, we’ll break down exactly what an ICCID number is, how to find and troubleshoot it, and why it matters for managing your devices at scale. We’ll also explore how it interacts with other key identifiers like IMSI and IMEI to keep your SIMs online, especially when navigating cross-border connectivity challenges.

Finally, we’ll touch on how advancements like eSIMs are changing the way these identifiers work in today’s dynamic IoT landscape.

What do the numbers in an ICCID mean?

While an ICCID might seem like just a long string of numbers, each section of the ICCID carries important information about the SIM card.  

Let’s take a closer look at the ICCID number from the emnify SIM card in the image below: 8988303000000614227.

• 89: These first two digits are always the same. They indicate that this is a telecommunications product typically associated with mobile networks, whether or not the SIM card is currently active.

• 8830: This part usually represents the country code. In this case, it tells us the SIM card is linked to Germany.

• 300: These digits are tied to the mobile network code (MNC), identifying which mobile network operator issued the SIM. This helps the SIM card connect to its home network. 

• 00000614227: This final set of digits is what makes each SIM card unique. No other SIM in the world has this exact sequence. This number is important for managing your SIM cards, whether you’re activating services or troubleshooting.

Can ICCID numbers be recycled or reused?

ICCID numbers are globally unique, and each SIM card is assigned an ICCID that distinguishes it across mobile networks. Once issued, an ICCID is permanently linked to that SIM card, ensuring accurate network and SIM management.  

However, ICCID recycling is a nuanced topic. While technically possible, it is generally avoided by network operators due to the risk of conflicts in system databases and network management platforms. Operators typically wait a long time before considering an ICCID for reuse—if they consider it at all—due to the following reasons:

• Operational risks: Reusing an ICCID can cause conflicting data in billing systems, device management platforms, and inventory databases. A recycled ICCID could mistakenly link to a different SIM or user, causing serious connectivity issues and misconfigurations.  

• Global uniqueness standard: The ITU-T E.118 recommendation ensures that ICCID numbers are globally unique. Although the standard doesn’t forbid recycling, operators generally treat ICCIDs as unique forever, minimizing the chances of reassignment.

While ICCID recycling may seem like a rare issue for any business managing a large number of SIM cards, it’s important to track deactivated ICCIDs to prevent potential errors in system databases. Keeping management platforms up-to-date ensures that recycled numbers don’t cause problems during reactivation or SIM swaps.

How to find the ICCID number  

1. On the SIM card or packaging

The easiest way to locate the ICCID is to check the SIM card itself or the packaging it came in. The number is typically printed directly on the card, making it easy to reference when you have the physical SIM in hand. 

2. Using AT commands for IoT devices

For IoT devices with embedded SIM cards, finding the ICCID often involves sending a simple AT command. Here’s how to do it for different modules:

SIMCOM modules: Use AT+CCID? 

Telit modules: Use AT#CCID 

Quectel modules: Use AT+QCCID 

Need more detailed instructions on using AT commands? Check out our step-by-step AT commands guide  

3. Using an API

When managing large volumes of SIMs, retrieving ICCID numbers via an API is one of the most efficient methods. Using an API call, such as those offered by the emnify SuperNetwork, allows you to access and manage ICCID data for all SIMs in one central location.

ICCID vs. IMSI vs. IMEI  

In addition to the ICCID, there are two other mobile network identifiers you should be familiar with: IMSI and IMEI. While the ICCID identifies your SIM card, IMSI identifies the specific subscriber, and IMEI identifies the specific device.

IMSI  

IMSI stands for ‘International Mobile Subscriber Identity’. It’s a mobile subscriber’s unique identification number. Like an ICCID, an IMSI is saved on the SIM card. Most SIM cards only store a single IMSI, which is associated with a list of networks the subscriber is authorized to access. emnify’s SIMs, however, are multi-IMSI, meaning they store multiple subscriber identities. This allows the SIM to change identities to access more networks and select the one with the best coverage.

An IMSI is not the same as a telephone number. The IMSI number has up to 15 digits and consists of three parts:

The first three digits are the Mobile Country Code (MCC). This can be used to determine the home country of the operator that issued the SIM card. The IMSI of European countries always starts with the number 2.

The following two or three digits are the Mobile Network Code, which represents the network the user is active in. For example, the number 01 represents Deutsche Telekom.

All subsequent numbers are specifically assigned to the user, and no two users share the same IMSI number.

IMEI

The International Mobile Station Equipment Identity, or IMEI for short, is one unique 15-digit serial number that can be used to uniquely identify each mobile radio terminal (your device). It includes four parts:

The first two digits indicate the reporting body identifier showing Type Allocation Code (TAC) by GSMA approval group.

The next six digits are the TAC.   

The six digits after that uniquely identify the individual device.  

The final number is the check digit, which helps prevent errors in equipment databases.    

There are also “software versions” of IMEIs, referred to as IMEISVs. In an IMEISV, there is no check digit, and the last two digits represent the Software Version Number (SVN).

Troubleshooting an ICCID number

If your device isn’t connecting as expected, the ICCID number could be at fault. Start by checking the SIM card or its packaging to ensure the ICCID is visible and matches the records in your management platform.

If it's missing or incorrect, retrieve the ICCID using AT commands, such as AT+CCID for SIMCOM modules or AT#CCID for Telit modules. Once retrieved, verify the number against your platform’s records. If the ICCID and platform data don’t align, update your system records or consider replacing the SIM.

The graphic below illustrates this troubleshooting process, helping you pinpoint and resolve ICCID-related issues effectively.

Optimizing IoT operations with effective SIM management

Managing IoT SIMs across different networks can be challenging, especially when connectivity issues or scaling operations come into play. That’s where understanding identifiers like ICCID, IMSI, and IMEI becomes essential. The ICCID, in particular, serves as your anchor for provisioning devices, troubleshooting issues, and keeping an accurate inventory of your SIM cards.

When you need to quickly resolve connectivity problems or onboard new devices, having easy access to the ICCID helps you execute these tasks smoothly. It’s not just an identifier—it’s your tool for efficient and precise connectivity management.  

With emnify’s IoT eSIM and SuperNetwork, you gain more than just visibility. Our platform provides multi-IMSI technology, remote SIM management, and access to over 540 networks in 180+ countries, giving you the flexibility to manage all your connected devices in one place. This means faster provisioning, quicker resolutions, and the ability to troubleshoot from anywhere.  

Ready to simplify your connectivity management?

Explore how the SuperNetwork can help optimize your IoT operations, or reach out to our team to learn how we can support your specific deployment needs.