Abstract: In offshore environments, cable-stayed bridges are frequently subjected to combined wind, wave, and seismic actions, which may considerably amplify the dynamic response of the structure. In this study, a numerical model of a cable-stayed bridge pylon located in the southeast coastal region of China was developed using SAP2000, and load models for wind, waves, and earthquakes were established based on local environmental characteristics. The dynamic responses of the pylon under individual wind, wave, and seismic loads were compared with those under combined multi-hazard loads. The response characteristics under single and combined actions were investigated, and the influence of the soil cover thickness on the tower-top displacement, tower-base bending moment, and pile-head bending moment was examined. The results indicate that the pylon response under wave action is periodic, whereas wind load induces persistent vibration accompanied by abrupt displacement changes at the crossbeam. Under the wind, wave, and seismic load return periods adopted in this study, the wind load plays a dominant role when the three hazards act jointly; the seismic action can cause an instantaneous surge in the structural response, whereas the wave load has a relatively minor effect. Owing to the mutual interference between the deformation states of the structure induced by different loads, the total response is not a linear superposition of the responses under each individual hazard. The pile-head bending moment is more sensitive to the soil cover thickness than the tower-top displacement and tower-base bending moment. For bridges located in seabed areas without soil cover, multi-hazard design should prioritize the strengthening of the pile foundation protection.