Neptunea polycostata is a species of sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks.
There is one subspecies: Neptunea polycostata aino <small>Fraussen & Terryn, 2007</small> (synonym: Neptunea polycostata var. sculpturata <small>Golikov, 1963</small>)
Cold northern seas, Sakhalin Island, and Hokkaido, Japan.