Abnormal tides wherein the water level remains high for a few days despite the absence of remarkable meteorological disturbances may occur due to incoming continental-shelf waves. In this study, it is assumed that the continental-shelf wave can be initiated off the Choshi coast; this wave will subsequently reach Tokyo Bay. First, the characteristics of tide anomalies are discussed on the basis of tide, wind, atmospheric pressure, and wave data obtained near Choshi. Second, several obvious cases of water-level propagation from Choshi to Tokyo Bay are collected by scrutinizing the tidal data at both stations. Finally, it is discussed how the adverse effects of abnormal tides induced by the continental-shelf waves may appear to be more serious if the sea level rise is dramatic.