A new genus of Gerridae, Floresiobates, is described from the island of Flores in the Lesser Sunda Islands of eastern Indonesia, with F. lattini n. sp. as the type species. Floresiobates is compared with Rheumatogonus Kirkaldy and Jucundus Distant, and these three genera are considered on the basis of various shared character states to be closely related. Illustrations of key characters and a distribution map are provided, accompanied by a discussion of the ecological setting in which the type series was collected, and a consideration of the biogeographic implications of this discovery.