Numerical simulations for both tsunamis and storm surges on the coast of Okinawa Prefecture, which are expected to be the most dangerous cases, were conducted to evaluate the possible inundation area and potential damage. The detailed topographic model derived form filtered LiDAR observation data was applied to inundation simulation. Nonlinear long wave theory was used in tsunami simulation. The third generation wave spectrum model (SWAN) and VOF method (CADMAS-SURF) were used to calculate wave height and overflow volume, respectively, in storm surge simulation. The simulation results were compiled in inundation maps and computer graphic animations, and they were distributed to municipalities along the coast to promote tsunami and storm surge disaster prevention measures.