Context Transboundary sharing of river water is not just an international problem, it also cascades down to regional, state and local levels. Water cooperation in the Brahmaputra River basin among China, India, Bhutan and Bangladesh has long been contested. However, it is unclear how the four countries can cooperate and what the cornerstones for their cooperation might be. Aims Better transboundary management of Brahmaputra requires a new direction from the current situation of fragmented cooperation, conflicts and disputes in the region and increasing threats of climate change. Methods To explore possible consensus, we conducted an advocacy coalition assessment of the four countries on the basis of the heterogeneous ecosystem services valued by each nation. Key results Whereas China and India are focused on politics, Bangladesh and Bhutan are primarily concerned about the basin in physical terms. Although each nation values the Brahmaputra in different ways, it is possible to initiate strong collaboration on the basis of shared beliefs. We found that hydropower-supported energy transitions for clean and affordable energy supply meet the needs and expectations of all nations, especially under the threats of climate change. Conclusions A sustainable energy change coalition can help reduce carbon emissions, acquire green energy, irrigate land in dry seasons, and manage disasters and increasing runoffs from melting glaciers. We conclude our paper with insights for each nation and hydropower development as a whole that might help the nations manage the Brahmaputra River more sustainably by overcoming their unmatched or mismatched values and interest. Implications Water in shared rivers can raise regional conflicts, but it does not have to if mismatched deep core beliefs among nations can be avoided through cooperation.