The four-month research study was designed to help streamline existing regional cooperation mechanisms in the Mekong subregion for stronger operation and development synergies. With support from the Association for Overseas Technical Cooperation and Sustainable Partnerships, MI detailed focus areas, priorities, progress, and achievements of 14 cooperation mechanisms, as well as their respective implementation processes. From the vigorous qualitative analyses, MI also recommended emerging development trends and needs the Government of Japan can consider contributing to in infrastructure, transport connectivity, sustainable management of water resources, among others, to deepen Mekong-Japan cooperation.