A new species of fiddler crab, Uca jocelynae sp. nov., belonging to the U. vocans complex, is described from the islands in Western Pacific on the basis of morphological and molecular data. The new species was previously identified with U. neocultrimana (Bott, 1973) (= U. vocans pacificensis Crane, 1975). The two species can be readily distinguished by characters of the male major chelae, carapace features, and the form of the vulvae. The molecular data of parts of the mitochondrial 16S rRNA and cytochrome oxidase I (COI) genes support that both are sister taxa but nevertheless distinct enough to be regarded as separate species. Uca jocelynae is widely distributed from the islands in the Western Pacific, while U. neocultrimana occurs in Fiji and eastwards.