What is SIM-binding? What DoT’s new rules mean for messaging apps

The Department of Telecommunications (DoT) has directed messaging platforms that use Indian mobile numbers to identify users to ensure their accounts remain linked to the registered SIM card in the device. The requirement is expected to take effect from January 1, 2027, following a compliance deadline of December 31, 2026.

The move aims to curb cyber fraud, identity misuse and scams carried out using Indian mobile numbers. Under the directive, covered messaging apps must ensure that their services remain linked to the active SIM used to register the account.

This means, a mobile that does not have a SIM card cannot be used to access messaging apps like WhatsApp and Telegram. Currently, a smartphone without a SIM card can be used to run these apps — all its needs is an internet connection via WiFi, etc.

What is SIM-binding?

SIM-binding is a security measure that links a messaging account to the registered SIM card present in the device on which the service is being used. Unlike conventional verification, which typically requires a one-time code sent to a mobile number, SIM-binding is intended to ensure that the registered SIM remains available and active.

Also read: 9,400 WhatsApp accounts banned in crackdown on digital arrest scams: Centre to SC

The DoT said fraudsters have exploited the ability to continue using messaging accounts even after removing the registered SIM. This has enabled some operators to use Indian mobile numbers to conduct scams from outside the country.

Which apps will be affected?

The DoT's directive covers WhatsApp, Telegram, Snapchat, JioChat, ShareChat, Josh and Arattai. Signal hasn’t responded to the government directives. These platforms use mobile numbers for user identification, registration or service delivery.

Reportedly, Snapchat is among the services named in the original directive, rather than being explicitly exempted. The requirements apply to the platforms specified by the DoT.

Social media services that primarily use email addresses or usernames for registration, such as Instagram, X and Reddit, are not among the platforms named in this directive. This means these apps can continue to be used even if the device lacks a SIM card.

What happens if the SIM is removed?

Under the rules, users may lose access to a covered messaging service if the SIM linked to their account is removed or becomes inactive. Access may be restored once the registered, active SIM is available in the device again.

Also read: SIM binding rules will disrupt WhatsApp use; no fix for major scams, says expert

The change could affect people who use messaging apps on Wi-Fi-enabled tablets or secondary phones without the registered SIM. Users with dual-SIM phones will also need to ensure that the SIM associated with their account remains active and available.

The requirements could pose challenges for travellers and Non-Resident Indians (NRIs) who remove their Indian SIM cards while abroad and use local numbers instead. Their access may be affected if the messaging app cannot verify the registered Indian SIM.

What about WhatsApp Web and linked devices?

The original directive also addressed access through web versions of messaging services, including WhatsApp Web, requiring periodic logouts and re-linking.

Also read: WhatsApp’s username feature: How is it different from Telegram and Signal?

The impact on users with multiple linked devices will depend on how the platforms implement the SIM-binding requirements.

Why such rules?

The DoT said the measure is intended to prevent the misuse of telecom identifiers in phishing, impersonation, digital arrest and other online scams. The government has cited the substantial financial losses suffered by Indian consumers due to cyber fraud as a reason for strengthening safeguards.

By requiring messaging accounts to remain linked to active, registered SIM cards, authorities hope to make it harder for fraudsters to operate accounts using Indian numbers without retaining the associated SIM in the device.