The ultimate guide to blocking a phone by IMEI: steps, codes, and effects

What is the IMEI and why is it crucial for the security of your mobile phone?

El IMEI (International Mobile Equipment Identity) is a unique numerical code, usually 15 digits long, that uniquely identifies each mobile phone in the world. It can be considered the equivalent of a DNI or passport for mobile devicesThis number is essential because:

Allows you to identify your terminal on the operator's network, regardless of the SIM card you use.
It is the key to blocking access to mobile networks in case of theft or loss.
It plays an essential role in international blacklisting systems for stolen devices.

You can find the IMEI in the invoice, on the label of the original mobile box, in the Settings menu ("About phone" or "Phone information") and using the universal code * # # 06 on the call keypad. For more details on how to manage device security, visit our guide on What does the green dot on your phone's lock screen indicate?.

On mobile phones with Dual SIM Two IMEI numbers appear, one for each slot. On older models, you can also find the IMEI under the battery or SIM card holder. If you've lost your phone, You can check the IMEI on the box, invoice or by asking your operator. if you recently purchased it.

Why is it important to write down and save your IMEI number?

Keeping your phone's IMEI is essential because Without this number you will not be able to block your device If it's stolen or lost, save a copy in a safe place: a photo on your computer, in a cloud, on paper, or locate the original phone box. The code *#06# only works if you have the phone in your hand, so always make sure you write it down.

How to locate your IMEI number from any device

In addition to traditional methods, there are alternatives to recover your IMEI even if you have already lost your phone:

Through Google, access 'Find your device' with your associated account and select the device. Click the information icon (i) to view the IMEI.
On Apple devices, go to iCloud.com and go to the Associated Devices section. There you'll see the IMEI of each registered iPhone.
Check your electronic purchase invoice if you purchased your phone online, as many stores include it on the receipt.

What does blocking a mobile phone by IMEI consist of?

Blocking by IMEI is an irreversible action (until you unlock it with the operator) This prevents the device from accessing mobile networks from any operator listed in the blacklist database. What happens when you block your phone by IMEI?

The phone can't make or receive calls, send or receive SMS, or use mobile data with no SIM card.
It is still possible to use basic functions such as the camera, music players, offline apps, or WiFi access if the system is not protected, it is therefore advisable to activate additional locks.
Your files are not deleted: IMEI blocking does not delete photos, documents or apps. If the thief manages to gain access inside, your data could be at risk.
IMEI blocking is effective mainly in countries adhering to the international database GSMA (most of Europe and the Americas). In other territories, the phone could be used normally.
The process is reversible: If you recover your phone, you can request its unlocking from the operator after verifying your identity.

What doesn't IMEI blocking do?

It is important that you know that blocking by IMEI does not delete your personal files from the device Nor does it prevent physical access to the system without a protected password, PIN, pattern, FaceID, or fingerprint. It also does not prevent the device from being disassembled for sale in parts. Therefore, always complements the IMEI lock with additional security measures (we explain it in detail below).

What does the green dot on your phone's lock screen indicate?

How to block your phone by IMEI step by step?

Follow these detailed steps according to your case and type of purchase:

File a complaint at the nearest police station (or online, depending on your country). Provide as much information as possible: IMEI number, make, model, description, and serial number, if possible. Keep a copy of the report.
Contact your mobile operator (Movistar, Vodafone, Orange, Yoigo, etc.) by phone, WhatsApp, online, in-store, or through the customer service section. Have your personal information, the report, and the IMEI number ready.
If you bought the mobile phone from a different operator, You will first need to register the IMEI with your current carrier. so that it is recorded in your database and you can process the block.
Request that your phone be blocked by IMEI. The carrier will ask for your identification information to validate ownership and process the process.
El Blocking can take from minutes to several days to complete, and up to months if multiple international carriers are involved. You'll receive a confirmation notification. Ask about the unlocking process if you get your phone back.

Note: Some carriers require a police report to process a blocking request. In some countries (such as Mexico), you can request it online or by phone (Locatel, Mexico City). Always check the fastest route for your country and carrier.

What happens to the device after it is locked?

By blocking your mobile phone by IMEI, you leave the terminal unusable for use on the mobile network. It literally becomes an “electronic paperweight,” although the internal hardware (camera, speakers, storage, display) may still function. The thief won’t be able to make calls or connect to mobile data, but You could use it as a media player, camera, or offline game console. if you are not fully protected.

Please note that in countries outside the international blacklist circuit, the terminal could be sold and used. In addition, generally, Network-level blocking does NOT affect stored contentIf your phone doesn't have a pattern, PIN, fingerprint, or Face ID, it's a good idea to lock it or wipe data remotely (we'll explain how later).

Is IMEI blocking effective worldwide?

IMEI blocking is effective in most countries in Europe and America, which are part of the GSMA blacklistsHowever, there are countries (especially in Africa, Asia, and some areas of Latin America) whose operators do not consult these lists, allowing blocked phones to be used normally there. Therefore, The lock is very secure in most major markets, but it is not 100% foolproof globally..

In addition, there are illegal techniques to change the IMEI of a device (called "flashing"), but they are complex, dangerous and illegal in most legislations..

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What steps should you follow if you recover your phone after it has been blocked?

If you are lucky enough to recover the terminal:

Contact your operator and request the unlock by IMEI providing the necessary documentation (cancelled complaint, proof of ownership, etc.).
The unlocking process can be immediate, take a few hours, days, or even weeks if the unlocking process has to be managed across multiple carriers.
Until it's unlocked, your phone will still not have access to the mobile network.

Important: Only the legitimate, accredited owner may request unlocking.

Additional security measures after theft or loss

Although IMEI blocking is essential, Protecting your personal information and accounts is equally or more importantThese are the key steps to follow:

Change your passwords immediately from your accounts (email, social networks, banking apps, etc.) associated with the lost device.
Block bank cards if you have financial apps or payment details saved.
Use remote tracking and wiping services like Google “Find My Device” or Apple “Find My Device.” You can try to locate it, lock it, and erase all data remotely if it’s still on and connected.
On Android: Access the official Google tool here to locate, ring, lock or erase the terminal.
On iPhone: from Search my Iphone (iCloud app or web), you can lock and erase content.

How to protect your phone before it gets stolen

The best protection is always prevention. Follow these tips to reduce risks and facilitate the recovery or blocking process:

Always save the IMEI in a safe place, away from your mobile phone.
Activate a secure locking method (PIN, pattern, fingerprint, FaceID). Set up the auto erase after several failed attempts, if available.
Do not save passwords directly on your mobile phone.. Use password managers with double verification.
Enable remote tracking and check that the location is always active.
Consider installing an anti-theft app or mobile insurance.

Frequently Asked Questions About IMEI Blocking

Can I block the IMEI from the Internet? In many countries and carriers, you can start the process online, but you'll generally have to complete the application by phone or by submitting a physical report.
Does blocking by IMEI erase my data? No. The phone's contents are still accessible if the thief gains entry.
Is IMEI blocking reversible? Yes, once you have recovered your phone, you can request that it be unlocked from your carrier.
Does it prevent full use of the device? No, it only blocks access to mobile networks, but all offline functions remain available if the system is not protected.
Does it work if you travel with your mobile phone to another country? If the country is included in the global database, the lock remains active. If not, the phone may operate on other networks.

Common mistakes and extra tips

Don't lock your phone until you're sure. that it has been stolen or permanently lost, since unlocking it may take several days or weeks.
Forget to save the IMEI number: Without it, the operator can't do anything.
Do not enable remote wipe or tracking options on your operating system.
Failure to notify the bank or sensitive services after the loss.

Legal implications and collaboration between operators

Operators are required to block a device by IMEI if the required documentation and a report of theft or loss are presented. The blockade is usually national and, in much of Europe and America, also international., thanks to GSMA agreements. However, times may vary due to internal processes or the updating of international white and black lists.

If you are a victim of theft, A police report is essential not only for the blockage, but also for making a claim against your insurance. (if you have one) and for possible investigations.

Blocking a mobile phone by IMEI: special cases and alternatives

In Mexico City: You can lock your mobile phone through Block your cell phone or by calling Locatel (56581111).
In SpainEach operator has its own protocol (Movistar, Orange, Vodafone, Yoigo, etc.). Consult their website, phone numbers, and specific procedure.
To iPhone: In addition to blocking the IMEI, use the “Search” function to block and display a custom message or erase the device’s data.

How to act after a theft or loss: Quick checklist

Try locating the device using the official tools for your operating system.
Change all associated passwords.
Contact your bank and block any cards associated with them.
File a complaint as soon as possible and request an IMEI blocking from your carrier.
Let your contacts know about the situation to avoid potential impersonation attempts.

The security of your data and the protection of your device depend on awareness, prevention, and quick action. IMEI blocking is an essential tool, but it's not the only one, nor is it necessarily sufficient to protect all your information. Be aware of the importance of your IMEI, always keep this information in a safe place, and act decisively in case of loss or theft. Acting quickly can make the difference between a scare and a big problem.

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