This chapter provides a nuanced perspective of China’s role and positioning in the South-East Asia where the Mekong River is shared among six riparian countries. The Mekong River is strongly influenced by the monsoon season. The Lower Mekong countries have differing levels of reliance on the Mekong River, and each country has shown differing interests and focuses in water management, depending on its natural endowment. This chapter analyses China’s position evolving position regarding the Mekong River. It indicates that China has become more proactive in managing its transboundary interests, forming limited institutional arrangements with the existing regional mechanism on the management of the Mekong River. However, China has vested various interests in transboundary water-sharing that serves its economic and strategic interests. Regional development of Yunnan and Guangxi Provinces has been a priority in how it appropriates the Mekong River’s water resources. With the Lower Mekong countries exhibiting varying levels of water security on the Mekong River, in the long term the role that China plays at the basin level remains uncertain.