Calcinus hazletti Haig & McLaughlin, 1984, previously known only from Hawaii, is recorded from Japanese waters. This represents a major range extension to the northwest. A full description and detailed illustrations are provided for better understanding of the species. Most of the males examined in this study possess small gonopores on the coxae of the third pereopods (= female,gonopores). Calcinus haigae Wooster, 1984, very closely related to C. hazletti, is also redescribed in detail. Mouthparts of both species are described for the first time. The affinities and taxonomic problems among C. haigae and its colour variant, and C. nitidus var. australis Bouvier, 1915, considered a synonym of C. rosaceus Heller, 1861, are discussed.