Boninpagurus acanthocheles, a new genus and new species of hermit crab (Decapoda: Anomura: Paguridae) from shallow waters of the Ogasawara (Bonin) Islands, Japan, is described and illustrated. The new genus is characterized by the following characters: in males, the coxa of the right fifth pereopod has a straight or slightly curved, elongate sexual tube that is about 2–3 times the coxal length, directed laterally or posterolaterally, the proximal portion of the tube being stout and opaque and the distal portion transparent; the coxa of the left fifth pereopod has a short protrusion of vas deferens; females have paired gonopores and lack first pleopods. The new genus is similar to Anapagrides in several diagnostic features, from which it is distinguished by morphology of the male sexual tubes, the fourth pereopods, and female gonopores.