The study was conducted to assess the quality of surface water environment in the coastal area of Tien Giang province. The samples were collected in the dry season (March-June) and in the wet season (September-November) in 2020. The water quality variables of pH, dissolved oxygen (DO), total suspended solid (TSS), chemical oxygen demand (COD), ammonium (N-NH₄⁺), sulfide (S^2-), chloride (Cl^-), Coliform, zinc (Zn), arsenic (As), chromium (Cr), oil & grease were compared with QCVN 10-MT :2015/BTNMT. CA and PCA are used to cluster water quality and define monitoring criteria. Research results show that pH, Zn, As, Cr, Oil and Grease, Coliform are still within the allowable limits. COD ranges from 7 to 18 mg/L; The sulfide concentration detected only in March was in the range of 0.8-1.6 mg/L; The Cl^- concentration at the sampling sites ranged from 6,447 to 12,752 mg/L. TSS at sampling locations exceeded the allowable limit of QCVN 10-MT:2015/BTNMT from 1-1.7 times while TSS between months exceeded the allowable limit from 1.12 to 1.9 times. N-NH₄⁺ concentration exceeds the allowable limit of QCVN 10-MT:2015/BTNMT according to sampling location from 1-1.4 times and seasonally from 1-1.6 times. Overall results show that coastal seawater in Tien Giang province is lightly polluted with organic matter and N-NH₄⁺. Water quality has seasonal fluctuations in which DO, TSS, S^2-, Cl^- in the dry season are higher than those in the rainy season. In contrast, COD, N-NH₄⁺ in the rainy season were higher than those in the dry season. Water quality is classified into three clusters due to the difference of indicators COD, TSS, N-NH₄⁺, Cl^-. Cluster 1 is more polluted than the other clusters. PC1-PC4 were the main component explaining 73.4% of water quality variation. The indicators having the main influence on water quality in the study area include pH, COD, DO, TSS, N-NH₄⁺, S^2-, Cl^-, coliform, and Zn, which need to be continuously monitored. Further studies should focus on investigating sources of pollution in order to have a solution to better manage water quality in coastal areas.