Thailand was fourth, followed by the Philippines, Japan and Taiwan, it said based on a review of searches made on its platform in May and June this year.
Indonesia, Vietnam and Singapore rounded off the top 10.
Agoda said Indian vacationers are most interested in diving into water to beat the heat after a prolonged heatwave in May and June.
The Indian capital, New Delhi, experienced its longest and most severe heat wave in 74 years this year, with temperatures exceeding 40 degrees Celsius for 39 consecutive days, The Economic Times reported.
Many Southeast Asian countries including Vietnam also experienced record-breaking temperatures this year, resulting in school closures and health warnings.