Telkomsel Indonesia

Telkomsel Indonesia's RoaMAX eSIM provides roaming in 85+ countries with VoLTE support, meaning crystal-clear voice calls in Vietnam without the audio quality drop of older network standards. As Indonesia's largest carrier, Telkomsel has solid partnerships across Southeast Asia. Their eSIM setup is quick, and the plans work well for both short trips and longer stays.

This fits travelers starting from Indonesia or those who value call quality during their Vietnam trip. The VoLTE advantage means you'll sound clear whether you're calling business contacts or catching up with friends. Compared to standard roaming, the speeds and reliability in Vietnam are solid, though you'll want to compare data allowances with other regional options before committing.