Two new species of leucosiid crabs, Heteronucia toyoshioae and H. granulata, are described from the offshore banks of the Ryukyu Islands in southern Japan and the Izu Islands in central Japan. Heteronucia toyoshioae may be distinguished from all the known species of Heteronucia Alcock, 1896 by having seven tubercles on the carapace, a median triangular tooth on the sixth segment of the male abdomen, and the shape of the male first pleopod. Heteronucia granulata is similar to H. globata Sakai, 1963 and H. perlata (Sakai, 1963) from East Asia but can be distinguished by the presence of a small tubercle on the pterygostomian margin, a ridged row of granules on the branchial region, and a triangular tubercle on the posterolateral margin of the carapace.