This study utilizes the SWAN model to simulate wave data, subsequently comparing it with ERA5 and CMEMS wave reanalysis datasets. Our analysis demonstrates that the SWAN-simulated wave data are more consistent with observations compared to ERA5 and CMEMS reanalyzed wave data. The predominant wave directions are Northeast and Southwest, with occurrence frequencies of 43.87% and 24.24%, and maximum significant wave heights of 7.72 m and 3.28 m, respectively. Significant wave heights for 50 and 100 year return periods are 8.17 m and 8.53 m in the NE direction, 3.44 m and 3.56 m in the SW direction, 3.78 m and 3.84 m during the Southwest monsoon, 10.09 m and 10.45 m during the Northeast monsoon, and 12.8 m and 13.6 m during storms, respectively. These results are instrumental for the structural design of the Thien Nga - Hai Au oil field in the Southern region of the East Sea Viet Nam.