Learn how users with BSNL 4G or 5G SIM cards can activate this VoLTE feature. Send a message to 53733 with the text ACTVOLTE. VoLTE will be activated on your phone once you send the message.

BSNL also reiterated its commitment to completing ... the company plans to introduce supplementary services like Voice over LTE (VoLTE) and Voice over Wi-Fi (VoWiFi) in a gradual, phased approach.