For over 30 years, IHP (International Hydrological Programme) has been actively operating as a UNESCO’s (United Nations Educational, Scientific and Cultural Organization) international scientific cooperative programme in water research, water resources management, education and capacity-building, and the only broadly-based science programme of the UN (United Nations) system in this region. By a number of initiatives and networks, the IHP has progressively carried out activities on the quantity and quality of global/regional water resources, transboundary water resources management, mitigation of water related hazards, and water education. While addressing comprehensive areas over water challenges, greater emphasis has been placed on the role of water resources management for sustainable development and with respect to the expected changes in climate and environmental conditions. WWAP (World Water Assessment Programme) and its major product WWDR (World Water Development Report) in East Asia are under the framework of IHP which supports field oriented activities on monitoring freshwater, developing case studies, enhancing national assessment capacity, and facilitating decision making processes. In light of transboundary waters in IHP, RSC (Regional Steering Committee) plays a focal role for facilitating regional cooperation in the Southeast and East Asia and Pacific States. Furthermore, ISI (International Sediment Initiative) and IFI (International Flood Initiative) have significant roles, respectively, for the management of erosion and sedimentation in line with river system or reservoir management, and for the flood management focusing on capacity building of each country in East Asia. There are other major areas of concern under UNESCO’s IHP programme in East Asia, specifically in aspects including, mitigating water conflicts on transboundary aquifers through ISARM (International Shared Aquifer Resources Management), water management of arid areas through Water and Development Information for Arid Lands- A Global Network (Asian G-WADI), and sustainable management of groundwater by UNESCO Water Chair, as well as water education through the programme of Sustainable Water Integrated Management- Educational Component.