This paper develops a coupling between SWAN and Thetis models to account for wave–current interactions occurring by the co-existence of wave and current flows. The different grids and time-steps employed by the model components allow greater flexibility. The two models run consecutively, and communicate internally to exchange the necessary parameters. These are the significant wave height, mean wave direction, mean wavelength and percentage of wave-breaking calculated by SWAN necessary for calculating radiation stress and wave roller effects, while Thetis provides water elevation and current velocity fields.