A significant criticism of international legal frameworks and the solutions offered is their State-centric character. Age-old ties between transboundary communities and traditional knowledge (TK) being utilized to manage natural resources have yet to be used by governments to answer environmental issues. Decision-making thus remains unattached from considerations operating at the ground level. Even stakeholders close to natural resources cannot establish a connection with excessively centralized decisions made without their democratic involvement. This has proved to be true even for the management of transboundary freshwater sources, which have time and again become a subject of international disputes. Some case studies show that local-level decision-making involving local communities from across the border has proved to be of far greater utility for resolving riverine communities’ social and economic problems. This stands in comparison to what bilateral negotiations between nations could ever attain. An excellent example is transboundary dialogues called Mahakali Sambad, led by Oxfam and partner organizations. Another Oxfam project called Nodi Boithoks in the Meghna River basin has also resulted in the revival of age-old techniques, like Bandal or traditional check dams. These nature-based solutions (NbS) are not acknowledged by international treaties, which, especially in the South Asian context, have yet to yield any positive results. Therefore, the need of the hour is to take inspiration from the organic solutions and encompass them within international law. In the present paper, an attempt will be made to examine the successful case studies from across the world where NbS has given sustainable solutions for riparian issues and their feasibility of inspiring the creation of novel legal principles for governing transboundary rivers in South Asia.