IMEI Vs IMSI Number: What You Need To Know About Them

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Edgar Nicov

How-To

5 min. read

Published on October 3, 2025

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The world of mobile technology is filled with acronyms and technical terms that can be confusing. Two of the most common, yet often misunderstood, terms are IMEI and IMSI. While both are identification numbers associated with your mobile device, they serve different purposes and reside in different parts of the network. Understanding the distinction between these two is crucial for anyone looking to secure their device, troubleshoot network issues, or simply gain a better grasp of mobile technology.

This article aims to demystify IMEI and IMSI numbers, explaining what they are, how they differ, and why they are important. By the end, you’ll have a clear understanding of these essential identifiers and their role in the mobile ecosystem.

What’s the Difference Between IMEI and IMSI Numbers?

Understanding the IMEI (International Mobile Equipment Identity)

The IMEI, or International Mobile Equipment Identity, is a unique 15-digit serial number that identifies a specific mobile device. Think of it as your phone’s fingerprint.

Purpose: The IMEI is used to identify the device on a mobile network and can be used to block a stolen or lost phone from accessing the network, even if the SIM card is changed.
Location: The IMEI is embedded in the phone’s hardware and is not stored on the SIM card.
Finding Your IMEI:

Dial *#06# on your phone. The IMEI will be displayed on the screen.
Check the phone’s settings menu. The location varies by device, but it’s often found under “About Phone” or “General” settings.
Look for the IMEI printed on the phone’s packaging or on a sticker under the battery (if the battery is removable).

Decoding the IMSI (International Mobile Subscriber Identity)

The IMSI, or International Mobile Subscriber Identity, is a unique number associated with your SIM card and identifies you, the subscriber, on the mobile network.

Purpose: The IMSI is used to identify the subscriber and authorize their access to the mobile network. It’s essential for billing and network management.
Location: The IMSI is stored on the SIM card itself, not the phone.
Finding Your IMSI:

The IMSI is not typically accessible directly through the phone’s user interface for security reasons.
You may need to contact your mobile carrier to obtain your IMSI number.
Specialized apps or SIM card readers can sometimes be used to access the IMSI, but these are generally used for technical or forensic purposes.

IMEI vs IMSI: A Comparison

Here’s a table summarizing the key differences between IMEI and IMSI numbers:

Feature	IMEI (International Mobile Equipment Identity)	IMSI (International Mobile Subscriber Identity)
Identifies	Mobile device	Mobile subscriber
Stored On	Phone’s hardware	SIM card
Purpose	Device identification, blocking stolen devices	Subscriber identification, network authorization
Can Be Changed	No (without specialized tools)	Yes (by changing SIM card)
Accessibility	Easily accessible through phone’s settings or by dialing `*#06#`	Typically not accessible directly through the phone.

Why Are IMEI and IMSI Numbers Important?

Both IMEI and IMSI numbers play crucial roles in mobile network security and functionality.

Security: The IMEI allows network operators to block stolen phones, preventing them from being used on any network. The IMSI helps prevent unauthorized access to the network and ensures accurate billing.
Troubleshooting: Both numbers are essential when troubleshooting network issues with your mobile carrier. They can use these identifiers to diagnose problems and provide support.
Device Tracking: In some cases, law enforcement agencies can use IMEI numbers to track stolen devices.

Tips for Protecting Your IMEI and IMSI

Keep a record of your IMEI: Store your IMEI number in a safe place in case your phone is lost or stolen.
Protect your SIM card: Treat your SIM card like a credit card, as it contains your IMSI and other sensitive information.
Be cautious of phishing scams: Do not provide your IMEI or IMSI to untrusted sources, as they could be used for malicious purposes.
Report lost or stolen phones immediately: Contact your mobile carrier to report a lost or stolen phone and have the IMEI blocked.

Understanding Mobile Identifiers

Understanding the difference between IMEI and IMSI numbers empowers you to take better control of your mobile security and troubleshoot potential network issues more effectively. These unique identifiers are the foundation of how mobile networks identify devices and subscribers, ensuring a secure and reliable mobile experience.

FAQ

What happens if I change my SIM card? Changing your SIM card changes your IMSI number, as the IMSI is stored on the SIM. Your IMEI remains the same because it’s tied to the device itself.

Can someone track my phone using my IMEI number? Yes, law enforcement agencies can use the IMEI number to track a stolen device.

Is it safe to share my IMEI number? It is generally safe to share your IMEI number with trusted sources like your mobile carrier or when reporting a lost or stolen phone. However, avoid sharing it with untrusted sources.

What if my IMEI number has been blacklisted? If your IMEI number has been blacklisted, it means your phone has been reported as lost or stolen and blocked from accessing mobile networks. Contact your carrier to resolve the issue.

How do I find my IMEI number on an iPhone? You can find your IMEI number on an iPhone by going to Settings > General > About, or by dialing *#06#.