This study presents a rare sesarmid cavernicolous crab, Karstama boholano (Ng, 2002), from Taiwan. This genus and species are both new to Taiwan. We describe the diagnostic characteristics of the Taiwanese specimen and provide illustrations of the adult and first zoea, as well as photographs of an adult in its natural habitat. The identity was confirmed by the COI gene sequence and morphological data. In addition, the zoeal morphology and breeding ecology of the genus Karstama Davie and Ng, 2007 are reported for the first time.