The Vietnamese Mekong Delta (VMD) is an example of a complex dynamic socio-hydrological system in which societies and hydrology interact and co-evolve. The dominant engineering approach in the VMD has enhanced the dynamics of society and hydrology. This study looks at the implications of socio-hydrological dynamics in the coastal VMD where saline water is controlled by various infrastructures. In the first phase, key informant interviews and focus group discussions were used to explore socio-hydrological dynamics in the study area. The results show divergence in livelihood strategies inside the freshwater-projected area, shaping a heterogeneous agricultural landscape of fresh- and brackish-water livelihoods manifested by four socio-hydrological groups. Next, the Motivation and Ability (MOTA) framework and household surveys were used to assess the adaptability in the agricultural development pathway advocated by the freshwater policy. The result revealed differentiations among these socio-hydrological groups. The findings suggest other practices may be required to help the area navigate towards future adaptations to socio-hydrological changes.