Water has always been central to human survival and innovation, shaping both subsistence strategies and the development of complex societies. This session explores the diverse ways in which prehistoric communities in East and Southeast Asia managed and interacted with water resources, and how these practices contributed to broader trajectories of social complexity. We invite contributions that examine water from multiple perspectives: environmental archaeology, subsistence economy, and material culture. Topics may include but are not limited to irrigation systems, settlement moats, wetland exploitation, shellfish gathering and consumption, fisheries, and the symbolic or ritual dimensions of water. By highlighting a wide range of evidence – from farming practices to defensive architecture and aquatic food resources-this session seeks to foster a comparative understanding of the distinctive pathways through which water management shaped social and cultural developments in East and Southeast Asia. Of particular interest are discussions of how water-related practices influenced community organization, political authority and interregional interaction, as well as how these trajectories differed across the region. Through this lens, the session aims to identify both shared patterns and unique features in the prehistoric relationships between people and water in East Asia.