Shallow water wave hindcasting for each of many intense storms in the past 23 to 29 years is conducted separately in 3 sea areas of the Seto Inland Sea. The wind distributions are made on the basis of a spatial interpolation of wind data measured at many sea and coastal stations. An extreme value analysis yields estimates of 50-year return wave height and its confidence interval in the areas. A hindcast-based return wave height at each of 10 measurement stations is shown to give reasonable estimates. The return wave height is 9-11 m in the sea areas connected to the open sea, 7m in the strip areas of the inner sea where open sea waves propagate directly and a maximum of 5 m in the area dominated by local wave generation. A reanalysis of data in the public domain produces a rough agreement with the present estimate.