In settings where some resistance and rampant misinformation against vaccine exist even after it becomes increasingly available, the prospect of accelerating the progress to end the COVID-19 pandemic is rather bleak. To address this issue, we conduct a personalized- information intervention targeted towards unvaccinated individuals aged 18+ years old. For this purpose, we recruit ambassadors—laypersons, health cadres, and influential individuals—from local villages to deliver a comprehensive set of information on COVID-19 vaccine and promote vaccination using an interpersonal behavioral change communication approach which requires the ambassadors to deliver tailored information to each individual through two one-on-one meetings. To investigate which type of ambassadors is the most effective in conducting this task, we conduct a cluster randomized experiment in rural West Java, Indonesia that varies the ambassadors at the village level. We planned to recruit 3,600 unvaccinated individuals spread across 300 villages in three districts in West Java, Indonesia.