This study presents a method to assess the value of the ecosystem and recreation of beaches on a nationwide scale, and impacts are assessed both without and with the optimal beach nourishment as adaptation to beach erosion due to sea level rise for RCP2.6 (0.39-0.47 m) and RCP8.5 (0.55-0.65 m). The optimal nourishment would cost about 660 billion yen for RCP2.6 and 110 billion yen for RCP8.5. Without nourishment, the Japan's total beach would disappear 84% for RCP2.6 and 94% for RCP8.5 by the end of 21st century. With nourishment, the optimal beach loss rate is estimated 57% for RCP2.6 and 70% for RCP8.5 by the end of 21st century. Considerable limitations remain due to the lack of consideration to ecosystems except beach plants, impacts of grain size on ecosystems, and frequency of beach nourishment.
