This study focuses on the changes in wave energy in response to tidal currents in the western sea of Jeju Island where high-energy wave conditions along with strong tidal currents are usual. Here, an ocean-wave coupled modeling system was used to investigate the effect of tidal currents on the wave energy condition. A comparative experiment with and without tidal currents shows that the current largely affects wave energy in terms of the wave spectrum as a response to the relative direction between waves and currents. When the direction of the tidal current is the same as that of wave propagation, the magnitude of wave height is reduced with energy transfer from shorter periods of 7–9 s to longer periods of 10–12 s, resulting in a decrease (increase) of shorter (longer) wave energy. This reaction is reversed when the tidal current flows in a direction opposite to that of wave propagation. The uncoupled model tends to overestimate/underestimate the wave energy during the ebb/flood tides when the waves follow/oppose the currents by approximately 25%. This study demonstrates that ocean-wave coupling is capable of improving model wave conditions, and therefore, this model is useful for estimating potential wave energy resource and candidate sites.