Our knowledge on global distribution of the four extant horseshoe crab species is inadequate. The aim of this study (and the associated data set) is to improve our understanding of the current biogeographic distribution of horseshoe crabs. To do this we collated all available occurrence information for all four species on the Atlantic coasts of Central and North America, and the coasts of South-East Asia. Occurrence data from the four extant species of horseshoe crabs (Limulus polyphemus, Carcinoscorpius rotundicauda, Tachypleus gigas, and T. tridentatus) were compiled from recent literature, our scientific network, and own field work. The three Asian species C. rotundicauda, T. gigas and T. tridentatus were found to co-occur on the Indonesian islands Borneo and Java.