Step-by-Step Guide to Permanently Blocking a Lost or Stolen SIM Card

Has your phone been lost or stolen? The fastest way to protect your personal data and prevent fraud is to block your SIM card permanently. This guide explains step-by-step how to block a SIM card across different carriers, what happens after blocking, and additional measures for iPhone and Android users.

Part 1. What Does Blocking a SIM Card Mean?

Blocking a SIM card is the process of requesting your mobile carrier to deactivate your SIM, either temporarily or permanently. This prevents anyone from using your SIM card without permission.

Why it matters:

• Prevent unauthorized calls and messages: No one can make calls or send texts using your SIM.
• Protect your financial information: Stops fraudulent transactions linked to mobile banking or payment apps.
• Safeguard your identity: Prevents misuse of personal data stored or linked to your SIM.

Key points to know:

• Blocking can be temporary or permanent, depending on your carrier and your needs.
• After blocking, your SIM cannot be used on any phone unless reactivated or replaced.
• For iPhone or Android users, blocking the SIM is an important step, but additional security measures like remote device tracking and data erasure are recommended.

Part 2. How to Block a SIM Card Immediately

When your phone or SIM card is lost or stolen, acting quickly is crucial. There are 3 main methods: via customer care hotline, online portals or apps, and visiting a carrier store.

Method 1: Blocking SIM via Customer Care Hotline

Best for: Urgent cases without internet access.

Step 1. Call your carrier’s hotline (usually 24/7).

Step 2. Provide your lost SIM number and verify your identity.

Step 3. Request immediate SIM blocking.

Example:

Method 2: Blocking SIM via Online Portal or Mobile App

Best for: Users with internet access and account credentials.

General Steps:

 Step 1: Log in to your carrier account (portal or app).

Step 2: Navigate to SIM/device management or deactivate SIM section.

Step 3: Follow OTP/email verification to confirm the block.

Examples:

Method 3: Visit the Carrier Store to Block the SIM Card

Best for: Those who prefer in-person verification or need an immediate SIM replacement.

Steps:

Step 1: Bring a valid photo ID.

Step 2: Request SIM blocking and/or replacement.

Step 3: Carrier verifies your identity and blocks the SIM on the spot.

Quick Comparison of Methods

Additional Security Tips for iPhone and Android Users

• iPhone: Enable Find My iPhone and consider erasing your device remotely.
• Android: Use Find My Device or similar service to lock, locate, or erase your phone.

Part 3. What Happens When Your SIM Card Is Blocked?

Blocking your SIM card online ensures

• Immediate protection from SIM swap fraud
• Prevents unauthorized access to OTPs, banking apps, and personal data

Effects of blocking:

• Calls, texts, and mobile data stop working.
• You cannot use the SIM until it is unblocked or replaced.

Part 4. How to Unlock a SIM Card Blocked by PUK

f your SIM has been blocked due to incorrect PUK entries, you can still regain access by following these careful steps.

Step 1: Find Your PUK Code

• Usually printed on the SIM packaging under a scratchable panel.
• Can also retrieve it from your carrier’s website or app. 

Step 2: Enter PUK Code Correctly

Step 3: If the SIM Card Is Permanently Blocked

Entering the wrong PUK too many times will permanently block your SIM.

Special Note for iPhone Users: If you see “SIM Not Supported” or “SIM Locked,” a tool like Passixer iPhone Unlocker can remove SIM/carrier locks.

Part 5. Solutions for a Permanently Blocked SIM Card

In some cases, your SIM may be permanently blocked. Here are the main solutions to regain mobile service and retain your number.

Solution 1: Carrier replacement SIM (keep the same number)

• Visit the carrier store, verify your identity, and receive a replacement SIM.
• Keep the same number; activation usually takes a couple of hours.
• Cost depends on carrier policy; often free or small fee.

Solution 2: Switch to eSIM (if supported)

You can switch over to an eSIM if your phone and carrier support it. Here is an example.

Example: AT&T (USA)

Step 1: Check compatibility by dialing *#06# (EID number indicates eSIM support).

Step 2: Order online via AT&T Prepaid eSIM Portal or visit an AT&T store.

Step 3: Connect to Wi-Fi, scan QR code, and follow prompts to activate.

Manual Entry: AT&T provides the SM-DP+ Address and Activation Code. Go to Settings > Cellular > Add eSIM > Enter details manually.

Duration: Within a couple of hours

Cost: Usually, it is free.

Solution 3: Use Passixer iPhone Unlocker (iPhone Only)

Passixer iPhone Unlocker is a professional software solution that allows iPhone users to bypass carrier restrictions and SIM locks instantly, without needing carrier approval. It also handles other common iPhone restrictions, including activation lock, screen passcodes, MDM, Screen Time passcodes, and iTunes backup encryption, while keeping your data safe.

Step-by-step Process:

Part 6. Tips to Avoid SIM Card Problems

To prevent SIM card issues in the future, follow these simple tips:

• Save your PUK code securely – keep it in a safe place in case you need to unblock your SIM.
• Use phone screen lock and two-factor authentication – this adds an extra layer of security for your data.
• Block your SIM immediately if your phone is lost or stolen – quick action prevents unauthorized use and fraud.

FAQs

Conclusion

Losing your SIM card or phone can be stressful, but taking quick action can protect your data and prevent fraud. After reading this guide, you should understand SIM locks, how to unblock SIMs, and what to do if your SIM or phone is lost. For iPhone users, tools like Passixer iPhone Unlocker provide additional solutions for bypassing carrier restrictions. Stay proactive, follow the steps, and you can remain worry-free.