In order to evaluate the changes in surface water quality in Kien Giang province, the study used discriminant analysis (DA) and principal component analysis (PCA). The 13 water quality indicators that were collected between years of 2019 and 2021 were T, pH, DO, BOD5, COD, TSS, N-NO2-, N-NO3-, N-NH4+, P-PO43-, Fet, Cl-, and Coliform. The federal government’s criteria for surface and marine waterways are used to measure the water quality. The results show that the water quality in the study region is startling and exceeds the permitted limits established by national technical standards. In comparison to the rainy season, the dry season exhibited higher concentrations of N-NO2-, N-NO3-, and Cl-. In both seasons, the study area’s surface water quality can only be used for irrigation and drainage. Human activities in residential, agricultural, industrial, and saline intrusion areas are the main sources of contamination. The PCA suggests including eight indicators in the long-term monitoring program: T, DO, BOD5, COD, N-NO2-, N-NH4+, P-PO43-, and Coliform because to their considerable impacts on the quality of surface water. TSS, N-NO3-, and Cl- are a few more water body metrics that are affected by seasonal fluctuations. The most current scientific discoveries offer vital data that will help maintain the quality of the surface water along the coast, including Coliform, COD, N-NO2-, N-NH4, and P-PO43-. Seasonal variations affected other TSS, N-NO3-, and Cl- characteristics of water bodies. The most recent findings provide critical scientific information for preserving the surface water quality in the coastal region.