Abstract The wave energy flux distribution in the Bohai Sea during wintertime is re-evaluated based on SWAN with the added sea-ice effect, which is derived from an ice-ocean coupled model, FVCOM. Simulated wave parameters and ice cover agree well with the measured wave data and the MODIS images of sea-ice cover, respectively. The results indicate that the decrease of wave energy flux is mainly caused by the formed ice which leads to the reduction of the effective wind fetch and transferred momentum from air to the ocean surface. The numerical results in a typical winter from 2011 to 2012 show that, due to the presence of sea ice, the average wave energy fluxes can be decreased by up to 80% in Liaodong Bay, while up to 50% in Bohai Bay and Laizhou Bay. Under the extreme winter-weather conditions, more pronounced reduction of wave energy flux caused by ice is observed. The findings also imply that in the design of wave energy converters (WECs) and their deployed locations in the Bohai Sea, even the likely ice-free areas in winter time, the effect of other ice-covered regions on the decrease of wave energy flux as a result of decrease in wind fetch should be considered.