The blue-spotted maskray from Guadalcanal Island (Solomon archipelago) is distinct by its colour patterns from Neotrygon kuhlii with which it was previously confused, and belongs to a genetic lineage clearly separate from all other known species in the genus Neotrygon. It is here described as a new species, Neotrygon vali sp. nov., on the basis of its nucleotide sequence at the cytochrome oxidase 1 (CO1) gene locus. It is diagnosed from all other known species in the genus Neotrygon by the possession of nucleotide T at nucleotide site 420 and nucleotide G at nucleotide site 522 of the CO1 gene.