The characteristics of highly nonlinear waves reflecting from a vertical wall in water of finite depths are investigated both experimentally and theoretically. In this study, we re-examine nonlinear interaction phenomena with a vertical wall on a sloping beach as the effects of slope, i.e. changing in water depth are not included in any previous studies. The results of regular-wave experiments indicate that the wave periods of individual standing waves become slightly longer than those of progressive waves. The periods of reflecting wave groups become also longer than those of progressive wave groups. In both cases, amplitude modulations in the reflected wave field are very significant for higher wave steepness while no amplitude modulation occurs in the progressive wave field.
