DoT's SIM Binding Rule Explained: What It Means for Messaging Apps and Users

The Department of Telecommunications announced a move towards stricter verification for messaging platforms through a new SIM binding requirement on December 1. Under the directive, messaging platforms were given a 90-day window to implement the changes, and three months have passed since the directive was issued. The rule aims to ensure that messaging app accounts remain linked to an active SIM card at all times. The policy aims to address rising cases of digital impersonation, financial fraud, online scams, and identity misuse conducted through app-based messaging services. An internet advocacy group has urged the DoT to recall its mandate for SIM binding in te\he country. 

What Is SIM Binding?

The new directive has been issued by the Department of Telecommunications as an amendment to the Telecommunication Cyber Security (TCS) Rules, 2024. The updated framework has been notified as the Telecommunication Cyber Security (TCS) Amendment Rules, 2025.

The legislation requires that the messaging service implement a continuous SIM validation, where the user account is required to remain associated with the active SIM card that was in place at the time of registration. The legislation had a 90-day implementation period for service providers.

The scope of the mandate includes messaging services that come under the category of Telecommunication Identifier User Entities, or TIUEs. This includes popular messaging services like WhatsApp, Telegram, Signal, Snapchat, and Messenger. SIM binding is touted as a method to ensure that the registered identity remains verifiable and linked to telecom subscriber records at all times.

This, according to the DoT, is in a bid to curb the growing instances of digital impersonation, financial fraud, online scams, and misuse of identity, all carried out via messaging apps. It has been observed that criminals are taking advantage of the app's feature that allows users to access the app even after the SIM is removed or deactivated, such as in the case of number recycling.

After the DoT announced mandatory SIM binding for messaging platforms, internet advocacy group Internet Freedom Foundation asked the DoT to recall the mandate, citing potential issues related to the implementation of SIM binding in the country. IFF highlighted various issues, stating that users would likely have to purchase an international travel pack to access WhatsApp while abroad, and that they might lose access to their chats if their SIM is damaged.

How SIM Binding Works

As explained by the DoT, SIM Binding links the user's messaging account with the SIM card currently inserted into the smartphone. This system guarantees that the phone number used during the account registration is active and verifiable through the records of the telecom subscriber. Under the new system, messaging applications are required to carry out continuous verification checks using a user's SIM card.

Service providers are also required to implement additional measures, for instance, restricting access to a user's account when their SIM card is removed or changed.

The new mandate is expected to impact people who switch devices frequently, replace SIMs, travel internationally with inactive domestic numbers, or use messaging apps across multiple devices. To continue using the messaging platforms, users must keep the same active SIM inserted in the primary smartphone used during the account registration process. If the number changes, users may need to re-register on the app or verify again.

How Apps Will Be Affected

The rules also include a requirement for implementing automatic logout systems for secondary devices. According to the directive, linked devices may be logged out periodically and require fresh authentication from the primary smartphone that contains the registered SIM card.

For example, WhatsApp Web users could be required to log in again every six hours through the main device where the SIM is installed. Similar changes could apply to services such as Telegram Desktop and other web or desktop messaging clients. In contrast, users can currently log into services and continue using them even if they change SIM cards or switch networks.

Messaging apps, notably, have already begun to prepare for compliance. WhatsApp has reportedly started working on SIM-binding-related features for users in India to align with the DoT directive. Per a feature tracker, the app will inform users that it must check that their SIM card is present in their smartphone to comply with regulatory requirements.