The Indus, Ganges, and Brahmaputra are few of the South Asian rivers that cross international borders and supply millions of people with essential water resources. As one of the least integrated regions in the world due to various conflicting issues, river water sharing, if harnessed properly, can be the cementing bloc among the South Asian Countries. Thus, cooperation on transboundary river water issues is crucial for promoting solidarity among South Asian countries. Hence, the chapter investigates the potential for using water as an instrument to strengthen solidarity rather than creating conflict in South Asia. To fulfill the given objectives, the paper has identified key points on which regional consensus can be made. It includes non-traditional issues like climate change, shared navigation, water pollution, etc. This focuses on how regional solidarity could be promoted by taking advantage of the shared rivers that run through South Asia. The five countries that make up the co-riparian basin—India, Pakistan, Nepal, Bangladesh, and Bhutan—are the subject of the study. The chapter concludes that transboundary river water has the potential to play a significant role in regional integration. The sharing of water resources can lead to cooperation and collaboration between neighboring countries, which can help to build regional solidarity in South Asia.