Hizen Kashima-higata is a tidal mudflat at the mouths of Shiota River and Kashima River on the western shore of the Ariake Bay. Although the Site is part of the Central Kuroshio Current biogeographical region, the water is brackish rather than marine because it is about 100 km away from the mouth of the Bay. The Site is internationally important in the life cycle of migratory waterbirds, acting as an important stopover and wintering site for globally threatened species such as the endangered black-faced spoonbill (Platalea minor),and the vulnerable Saunders’s gull (Chroicocephalus saundersi) and far eastern curlew (Numenius madagascariensis). It hosts more than 1% of the flyway populations of Saunders’s gull, black-faced spoonbill and whimbrel (Numenius phaeopus). The mudflat has a rich biodiversity, including fish, benthos, and halophytes, due to the warm climate, large tidal variation, and shoals which facilitate sediment deposition. Over the years, the extensive mudflats around the Ariake Bay have been subjected to land reclamation and the construction of dykes. As a result, Hizen Kashima-higata, together with the two other coastal Ramsar Sites in Ariake Bay, Arao-higata and Higashiyoka-higata, has an increasingly important role in biodiversity conservation in the Bay. Hizen Kashima-higata is also important for supporting the livelihood of the local communities and for its cultural value that stems from traditional fishing and recreational activities.