With the increasing construction of large-scale wind turbines in seismically active coastal areas, the survivability of these high-rated power offshore wind turbines (OWTs) in marine and geological conditions becomes extremely important. Although research on the dynamic behaviors of OWTs under earthquakes has been conducted in consideration of soil-structure interaction, attention paid to the impact of earthquake-induced seabed liquefaction on OWTs supported by large-diameter monopiles is limited. In view of this research gap, this study carries out dynamic analyses of a 10-MW OWT under the combined wind, wave, and earthquake loadings. This study uses a pressure-dependent multi-surface elastoplastic constitutive model to simulate the soil liquefaction phenomenon. Results indicate that the motion of the large-diameter monopile leads to more extensive soil liquefaction surrounding the monopile, specifically in the zone near the pile toe. Moreover, compared with earthquake loading alone, liquefaction becomes more severe under the coupled wind and earthquake loadings. Accordingly, the dynamic responses of the OWT are apparently amplified, demonstrating the importance of considering the coupling loadings. Compared with wind loading, the effect of wave loading on the dynamic response and liquefaction potential is relatively insignificant.