Two new freshwater crabs, Geothelphusa koshikiensis and G. mishima, are described from Koshiki Islands, and Uji, Kuchierabu and Kuroshima (one of the Mishima Islands) of Kagoshima Prefecture, southern Kyushu, Japan, respectively. Both species have previously been confounded with G. dehaani, widely distributed in Japanese mainland (Kyushu to Honshu). The new species are differentiated from one another and other congeners by morphological characters and coloration in life.
