What is an ICCID number?

Learn what an ICCID number means, how it identifies your SIM card, where to find it, and why it’s essential for mobile networks and IoT connectivity.

Skip to table of contents

The Integrated Circuit Card Identifier (ICCID) is a unique 18–22-digit code printed on every physical SIM card that helps identify the SIM itself. In short, it’s the SIM’s unique ID, the SIM ID.

Each number is globally unique and stored in the SIM’s chip. Mobile network operators use it to authenticate SIMs on cellular networks, link them to the correct subscriber account, and enable IoT connectivity across multiple mobile devices.

If you are wondering what does this code look like on my SIM card, you will usually find it printed on the SIM’s body, packaging, or in your phone’s settings.

These identifiers follow the ITU-T E.118 international standard and are stored in a SIM file called EFICCID.

Meaning and structure

This identifier follows a standard format:

MMCC IINN NNNN NNNN NN C x

Here’s what each part means:

  • MM: Usually 89, which designates telecom and SIM cards.
  • CC: Country or Mobile Country Code (MCC).
  • II: Issuer or Mobile Network Code (MNC), identifying the issuer identifier (your carrier).
  • N: The SIM’s unique serial number or individual account identification.
  • C: A checksum generated using the Luhn algorithm to verify integrity.
  • x: Optional internal digit not part of the official standard.

This structure makes each SIM globally traceable across cellular networks and IoT devices.

How mobile network operators use it

Mobile network operators (MNOs) rely on these identifiers to connect, manage, and secure millions of mobile and IoT devices.

1. Network access and authentication

When a device connects to a network, the code identifies the physical SIM card and verifies that it belongs to the correct operator.

2. Device and subscriber management

Each identifier links to a subscriber account, billing details, and service plan. This helps operators manage data plans, update network access, and locate a specific SIM if troubleshooting is required.

Example: If an IoT device stops sending data, the operator can check its SIM ID to confirm whether it’s active or suspended.

3. Security and fraud prevention

By monitoring activity, carriers can detect SIM swap or cloning attempts and block unauthorized use.

4. Roaming

When traveling, the number identifies your mobile network code (MNC) and ensures correct roaming partners and billing.

5. IoT connectivity and lifecycle management

In IoT deployments, these identifiers support remote provisioning and lifecycle management. They enable large-scale SIM tracking, data monitoring, and over-the-air configuration of connected devices.

ICCID vs IMSI vs IMEI vs MSISDN

Although these terms are often mentioned together, each one identifies a different part of the mobile ecosystem. Understanding how they interact helps distinguish between the SIM card, the subscriber, the device, and the assigned phone number.

Identifier Full meaning Purpose
ICCID Integrated Circuit Card Identifier Identifies the SIM card hardware
IMSI International Mobile Subscriber Identity Identifies the subscriber and account
IMEI International Mobile Equipment Identity Identifies the device hardware
MSISDN Mobile Station International Subscriber Directory Number The phone number assigned to the SIM

These identifiers work together to authenticate the SIM, subscriber, and device. The ICCID identifies the card, the IMSI identifies the user, the IMEI identifies the hardware, and the MSISDN is the phone number used for calls or messages. Changing a phone number does not change the SIM’s identifier.

How to find ICCID number

If you’re looking for how to find your SIM ID, there are several options:

On iPhone:

Go to Settings > General > About, then look for ICCID.

On Android:

Open Settings > About Phone > SIM Status, then look for ICCID or “SIM Serial Number.”

On IoT modules:

Use one of these AT commands:

  • SIMCOM: AT+CCID=?
  • Telit: AT#CCID=?
  • Quectel: AT+QCCID=?

eSIMs and identification numbers

Each eSIM also contains a unique identifier, though its structure works differently:

  • The eUICCID identifies the physical eSIM chip.
  • Each downloadable carrier profile has its own identification number, allowing multiple subscriptions on one device.

This setup makes eSIMs more flexible for roaming, carrier switching, and managing multiple profiles without replacing a physical SIM card.

Can the ICCID number be changed?

No. Each identifier is permanently assigned when the SIM or eSIM profile is created. Changing carriers or activating a new profile generates a new number.

Role in IoT and mobile connectivity

In IoT connectivity, these identifiers are essential for managing connected systems. They are used for:

  • Authenticating SIMs across networks.
  • Managing provisioning and activation remotely.
  • Tracking data usage and connectivity performance.
  • Preventing unauthorized device access.

From smart meters and connected cars to industrial sensors, this system ensures every device remains identifiable and securely connected throughout its lifecycle.

FAQs