Adota elongata sp. nov. is described on the Korean coast. Adults of the new species were collected under stones on the seashore and are similar to those of Adota koreana Lee & Ahn, 2013. Morphological comparison for these two species is presented. The validity of the new species was also supported on both parsimony and maximum likelihood trees using partial COI and 28S gene sequences. A description and illustrations of diagnostic characters are provided to facilitate identification.