Reissued SIM Numbers in India: Privacy Risks & Telecom Rules

By Ajit — Published November 23, 2025

In India, mobile numbers do not stay permanently with one user. When a SIM remains unused for a certain period, telecom operators deactivate it and eventually reassign it to a new customer. While this system helps manage the limited number pool, it also leads to privacy and security concerns, especially when sensitive information is still tied to the old number.

How Number Recycling Works

Inactivity and Deactivation

• Telecom operators can deactivate a number if there is no usage for a specific duration.
• TRAI/DoT mandates a 90-day cooling period before a deactivated number can be issued to a new user.

Return to the Pool and Reallocation

After the cooling period, the number is returned to the operator's number resource pool. As per MNP rules, operators coordinate with the number range holder to ensure smooth reassignment to new customers.

Mobile Number Revocation List (MNRL)

TRAI maintains an MNRL — a list used by banks, payment providers, and major service platforms to verify whether a number has been recycled. This system is not directly accessible to consumers but helps businesses prevent security risks.

Risks and Real-World Implications

Even with the mandatory 90-day waiting period, number recycling has several risks:

• Receiving OTPs or login links meant for the previous owner.
• Unwanted calls or sensitive messages from banks and services.
• Old accounts still linked to the number (UPI, banking apps, social media, etc.).

These issues create privacy risks and financial vulnerabilities, particularly where SMS-based OTP verification is used.

Before Taking a New SIM — Safety Checks

When getting a number that might be recycled, follow these checks:

1. Search the number on Truecaller and WhatsApp to identify any existing profile.
2. Add the number on messaging apps to detect previous activity.
3. Ask the retailer if the number is fresh or recycled.

If You Already Have a Recycled Number

Take the following steps to minimize security risks:

• Monitor incoming messages to identify stray OTPs or personal information.
• Verify with your bank that the number is not linked to any old account.
• Enable 2FA via apps instead of SMS where possible.
• Change recovery settings for major services to email or authenticator apps.
• Report unintended OTPs to your telecom provider and request verification.

Conclusion

Recycled numbers are a practical necessity for telecom operators, but they come with real risks. Although consumers cannot fully verify whether a number was previously used, basic checks and strong security habits help reduce vulnerabilities. Enable stronger authentication methods, review linked accounts, and stay alert during the first few days of using a new SIM.

FAQ — Frequently Asked Questions

Q: How long before a mobile number can be reassigned?

Telecom operators must wait for a 90-day cooling period before reassigning a deactivated number.

Q: Can consumers check if a number was recycled?

No official consumer tool exists. But you can check Truecaller, WhatsApp registration, and messaging apps for clues.

Q: What if I receive OTPs for the previous owner?

Do not use them. Inform your telecom operator and the respective service provider immediately.

Q: Are banking and UPI accounts affected?

Yes. If the bank hasn't updated its records, previous owners' accounts may still be linked to your number.

Q: How can I stay safe with a recycled number?

Use stronger authentication, monitor messages, and manually verify account linkages with your bank.