Songkhram River Basin (SRB), a wetland region and the largest Mekong tributary in the upper northeast region, is undergoing several changes. Understanding the impact of landuse change on the hydrological cycle is very important for a sustainable development and management of water resources in any watershed. This research aims to analyze the past landuse change, forecast the future the future landuse maps under various scenarios and finally analyze its impact on the water availability of SRB. The analysis of past landuse maps reveals a rapid conversion of crops, paddy and natural forest into rubber farms. The landuse change model DynaCLUE coupled with water yield module of InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs Tool) model was used to evaluate the impact of landuse change on the water availability based on different policy scenarios. Landuse maps up to 2100 were generated based on three future scenarios focused on economy, conservation and agriculture. The result of this study shows an increase in water yield under economic scenario as a result of increase in urban areas and rubber plantation whereas, a small decrease in water yield is seen under conservation scenario. However, no significant changes are seen under agriculture focus scenario. This study presents utility of landuse model analysis in foreseeing future landuse change impact on water availability. Thus, the results serve as model-backed reference to decision makers to formulate new policies or adjust the existing ones regarding landuse in SRB.