This study categorised the fishery districts in Iwate Prefecture, which were severely damaged by the Great East Japan Earthquake, using data on agriculture and fishery. Subsequently, changes in the industrial structure of coastal rural areas before and after the earthquake were clarified through an examination of both agriculture and fisheries at the same time. Using cluster analysis, district categories were classified into three cluster types (small-scale primary industry, large-scale primary industry and fishery-dominated clusters) before the earthquake and a fourth cluster (the three aforementioned clusters plus high population density clusters) after the earthquake. The industrial structure’s most significant change was in fishery-dominated clusters before the earthquake. After the earthquake, clusters with the characteristics of a high population density and small industries emerged. The change in the degree of population decline indicates that the loss of population has not accelerated in the districts where agriculture and fishery have been rebuilt in a balanced manner, although the scale may be either small or large. This finding suggests that both agriculture and fishery are important in coastal rural areas, just as the two were before the earthquake.