TL;DR
- An IMEI (International Mobile Equipment Identity) is a unique 15-digit number that identifies a mobile handset on cellular networks worldwide.
- Find your IMEI instantly by dialling *#06# or in Settings > About Phone on most devices.
- Networks use the IMEI to blacklist lost or stolen phones, rendering them unable to connect to any UK mobile network.
- Insurers require the IMEI to process claims and verify the device reported lost is the one actually insured.
- Changing or altering an IMEI is a criminal offence under the Mobile Telephones (Re-programming) Act 2002.
What an IMEI Number Is
The International Mobile Equipment Identity, universally abbreviated to IMEI, is a 15-digit numerical identifier assigned to every mobile handset before it leaves the factory. The IMEI is globally unique: no two legitimately manufactured handsets share the same number. It is allocated under a system managed by the GSMA (GSM Association), the international industry body for mobile operators and device manufacturers. The GSMA’s IMEI database, sometimes called the GSMA Device Registry, records the type approval and manufacturer information associated with each IMEI range. The standard is formally defined in 3GPP TS 23.003.
The 15 digits carry structured information. The first eight digits form the Type Allocation Code (TAC), which identifies the device model and manufacturer. The next six digits are the serial number assigned by the manufacturer within that TAC. The final digit is a check digit, calculated using the Luhn algorithm, which allows software to detect whether a number has been corrupted or manually altered. Understanding the structure is not necessary for everyday use, but it explains why an IMEI check can return information about the device model as well as its status.
How to Find Your IMEI Number
The fastest method, which works on virtually all GSM mobile phones regardless of manufacturer or operating system, is to dial *#06# from the phone’s keypad. The IMEI is displayed on screen almost instantly — no call is placed, and no charge is incurred. On dual-SIM devices, both IMEIs (one per SIM slot) are typically displayed simultaneously. Note both numbers down and store them securely off the device.
On iOS devices, the IMEI is also accessible at Settings > General > About; scroll down to the IMEI field. On Android, the path is typically Settings > About Phone > IMEI Information, though the exact wording varies between manufacturers and Android versions. The IMEI is also printed on the device’s original packaging (usually on a barcode label), and on many models it is engraved in the SIM tray or printed on the label beneath a removable back cover. Keeping a record of your IMEI in a secure location separate from the device is strongly recommended — if the phone is stolen, you will not be able to dial *#06# to retrieve it.
| Use | How the IMEI is used | Who uses it |
|---|---|---|
| Network blacklisting | IMEI added to Equipment Identity Register when phone reported lost or stolen; device barred from all UK networks | Mobile network operators via GSMA EIR |
| Insurance claims | Insurer verifies IMEI matches device stated on policy; confirms device is reported lost; prevents duplicate claims | Mobile insurers |
| SIM unlocking | Operator checks IMEI to confirm device eligibility for unlock (no outstanding debt, not blacklisted) | Network operators |
| Second-hand checks | Prospective buyer queries IMEI against blacklist and finance-check databases before purchase | Consumers; IMEI-check services |
| Law enforcement | Police use IMEI to trace ownership of recovered devices and link them to crime reports | UK police forces |
The IMEI Blacklist and How It Works
When a mobile phone is reported lost or stolen to a UK network operator, the operator reports the IMEI to the Equipment Identity Register (EIR), a shared database maintained by the GSMA on behalf of the global mobile industry. The EIR holds three lists: the white list (approved devices), the grey list (devices under observation), and the black list (devices barred from network access). Once on the black list, the handset cannot connect to any UK mobile network for calls, texts, or mobile data. The block is applied across all operators simultaneously, not just the one to which the theft was reported, because all UK operators query the same EIR.
This cross-operator blocking is the key mechanism that makes stolen mobile phones significantly less valuable on the secondary market. However, it does not prevent the device from being used on Wi-Fi, nor does it prevent it from being exported and used on networks in countries that do not share IMEI data with the GSMA EIR. Before purchasing any second-hand handset in the UK, running the IMEI through an independent check service — which queries the EIR and, in some cases, additional finance and insurance databases — is a straightforward due diligence step that takes under a minute.
Can the IMEI Be Changed?
Attempting to alter, remove, or re-programme a mobile handset’s IMEI is a criminal offence in the United Kingdom. The Mobile Telephones (Re-programming) Act 2002 makes it an offence to: re-programme a mobile phone so as to change its IMEI; have in your possession a device that has been tampered with in this way with intent to sell it; and possess equipment or software for the purpose of re-programming IMEIs. Penalties include imprisonment of up to five years and an unlimited fine on conviction on indictment.
The purpose of the 2002 Act is to close the loophole that previously existed when a stolen phone’s IMEI could simply be altered to circumvent a blacklist. While the legislation does not eliminate IMEI fraud entirely, it creates a substantial criminal deterrent and makes it significantly harder to legitimately sell or insure a phone with an altered IMEI. Any device showing an IMEI that does not match its original packaging, or that returns anomalous results on an IMEI check, should be treated as a serious risk.
IMEI and Insurance Claims
Most UK mobile phone insurance policies — whether standalone or bundled with a current account — require you to provide the IMEI of the insured device when taking out the policy and again when making a claim. Insurers use the IMEI to confirm that the device reported stolen or lost is the one that was actually insured under the policy, and to check whether the IMEI has appeared on the Equipment Identity Register as blacklisted, which corroborates the loss or theft report. Providing an incorrect IMEI — whether accidentally or otherwise — can result in a claim being rejected or treated as fraudulent.
When you take out mobile phone insurance, record your IMEI immediately and ensure it matches what is on your policy documentation. If the IMEI on the policy differs from the one on your actual device — for example because you replaced the device and forgot to update the policy — contact your insurer to correct it before you need to make a claim. Some insurers also cross-reference the IMEI against manufacturer records to verify the device model is consistent with the model stated on the policy.
What this means in practice
Seren receives her new Android handset and, before setting it up, dials *#06# to display the IMEI. She writes the 15-digit number on a piece of paper kept with her home insurance documents and also emails it to herself so she has a digital record. When she takes out a standalone mobile phone insurance policy the same day, she quotes the IMEI during the application and receives confirmation that it matches what the insurer has recorded. Six months later the phone is stolen on public transport. She immediately contacts her network operator to report the theft and have the IMEI blacklisted; the operator asks for the IMEI, which she has readily available. She then files an insurance claim providing the same IMEI. The insurer’s check confirms the IMEI is blacklisted on the EIR, corroborating her report, and the claim is processed without issue.
Related Guides
How we verified this
This article draws on the Mobile Telephones (Re-programming) Act 2002 as published on legislation.gov.uk; GSMA documentation on the IMEI standard and the Equipment Identity Register (including the GSMA Device Registry and 3GPP TS 23.003); Ofcom’s published information on handset blocking and unlocking obligations; and the ICO’s guidance on personal data associated with device identifiers.
Disclaimer: Kaeltripton.com is an independent UK editorial publisher. We are not regulated by Ofcom or the FCA and we do not sell or arrange mobile services, insurance, or financial products. This content is for general information only and is not legal, financial, or technical advice. Rules, prices, and operator policies change. Verify the current position with Ofcom, GOV.UK, the ICO, or your provider before acting. ICO registered ZC135439. Last reviewed: 2026-06-05.
Frequently Asked Questions
What is an IMEI number?
An IMEI (International Mobile Equipment Identity) is a unique 15-digit number that identifies a specific mobile handset on cellular networks globally. It is allocated under a system managed by the GSMA. Networks use it to identify devices connecting to their infrastructure, to block handsets reported lost or stolen, and to process unlock requests. No two legitimately manufactured devices share the same IMEI. The number structure encodes manufacturer and model information alongside a unique serial component.
How do I find my phone’s IMEI number?
The simplest method is to dial *#06# on the phone’s keypad; the IMEI appears on screen immediately without placing a call. On iPhones it is also found at Settings > General > About. On Android devices the typical path is Settings > About Phone > IMEI Information, though the exact wording varies by manufacturer. The IMEI is also printed on original packaging and, on many models, on a label in the SIM tray or under the battery. Note it down and store it securely off-device.
Can I change my IMEI number?
No. Altering or re-programming a mobile handset’s IMEI is a criminal offence under the Mobile Telephones (Re-programming) Act 2002. The offence carries a maximum penalty of five years’ imprisonment and an unlimited fine. It is also an offence to possess a device with a tampered IMEI with intent to sell it, or to possess equipment designed for re-programming IMEIs. The law was enacted specifically to prevent criminals from circumventing network blacklists by changing stolen phones’ identifiers.
What is an IMEI blacklist?
The IMEI blacklist is a list maintained within the GSMA’s Equipment Identity Register (EIR). When a phone is reported lost or stolen to a UK operator, the IMEI is added to the blacklist. Once listed, the handset cannot connect to any UK mobile network for calls, texts, or mobile data, regardless of which SIM is inserted. All UK operators share the same EIR, so a phone blacklisted by one operator is blocked across the entire UK network ecosystem.
Why do insurance claims need the IMEI?
Insurers require the IMEI to verify that the device being claimed for is the one actually covered under the policy, and to cross-check that the IMEI has been added to the Equipment Identity Register following the reported loss or theft — which corroborates the consumer’s claim. Providing an incorrect IMEI can lead to a claim being rejected. It is important to record the IMEI when taking out a policy and to ensure the number on the policy matches the actual device being insured.
