This study evaluates the potential of the Ice, Cloud and Elevation Satellite (ICESat) with the onboard Geoscience Laser Altimeter System (GLAS) instrument for the monitoring of water levels in river networks. The determination of water level estimations with GLAS altimetry data in the Mekong River (Southeast Asia) is evaluated. The research questions in this study aimed to develop a classification method to derive water level estimations and eventually water level trends in the Mekong River. Furthermore, the strengths and weaknesses of GLAS altimetry data for hydrological monitoring of water levels in the Mekong River are evaluated.