The key criterion for delineating the equivalent Class A navigation area in river-sea interfaces lies in wave conditions.Utilizing a nested mathematical model for third-generation wave growth and a combined model for wave growth and propagation,with measured waves as input and driven by continuous measured winds,long-term wave numerical simulations are conducted for the Qinzhou Bay waters of the offshore section of the Pinglu Canal to meet the requirements for navigation area declaration.The results show that compared with the wave height error of ERA5 simulated by the simulated wind field,the wave height error of the simulation by using measured waves and wind is significantly improved.By simulating a 5-year wave time series,the joint distribution of wave height and period,the significant wave height at the 5% probability level,and the wave condition boundary are obtained.According to this main basis,the equivalent Class A navigation area of Qinzhou Bay waters of the offshore section of the Pinglu Canal has become the first equivalent Class A navigation area approved by the Maritime Safety Administration of MOT.