Owing to global warming, sea-level rise (SLR) poses a serious threat to low-lying coastal areas. The potential impacts of SLR include inundation, coastal erosion, salinity intrusion, and degradation of coastal habitat. The Mekong River Delta (MRD) in southern Vietnam is a flat, low-lying land area that has experienced significant effects of climate change and SLR. Sea-level data collected from 1979 to 2006 show that the highest mean surface level of the spring tide has risen by 13 cm. This study investigated the impacts of climate change and SLR on sedimentation processes in the Tien River Estuaries of the Mekong River System. Long-term simulation results were obtained for the baseline and two SLR scenarios. In the low-SLR scenario, morphological evolutions of the Tien River Estuaries showed the same trend as the existing processes in the baseline, but intensified erosion and deposition processes. In the high-SLR scenario, the processes of erosion and deposition become too complex to estimate.