During a survey of the biodiversity of the southeastern part of Espiritu Santo, Vanuatu Archipelago, specimens of a tiny but distinctive new hermit crab species, referable to a new genus, were discovered in the shallow waters off the island. Herein, Pumilopagurus tuberculomanus new genus, new species, is described and illustrated. The genus is characterized by the development of a massive right cheliped, more than 0.7 total body length; male with a short left sexual tube directed from left to right across the ventral body surface and very short right sexual tube; and female with single left gonopore. Its relationship to other pagurid genera of comparable small body size is discussed.