Shell large (between 101.9 and 140.2 mm), thick and solid. Shape elongate, semi-oval, whorls rather convex, surface smooth occasionally with some weak striae, dull. Colour greyish brown.

Neptunea bulbacea has a characteristically big, heavy shell with a smooth but somewhat domed surface. Neptunea vinosa differs in having 2 strong spiral cords (or folds) along the periphery, a smoother surface, a brown colour without any greyish tinge and a smaller adult size.
Some smooth shells of Neptunea polycostata polycostata look similar but differ in having a thick spiral cord on the upper spire whorls and a larger adult size.

Neptunea bulbacea lives along the Russian coast of the Sea of Japan (Primorye) and south Sakhalin and is known from Stenina Island, the Strait of Tartary, the Gulf of Aniva and the Gulf of Terpeniya. Bathymctric range shallow, between 18 and 85 m. Recorded from 0 m, the littoral, of Kunashir Island (Kuril Islands) (Golikov & Kusakin, 1978: 173) and from 7 m in the Gulf of Aniva
(south Sakhalin) (Golikov & Scarlato, 1985: 409). The species is quite common as Golikov & Scarlato (1978:409) recorded a mean density of 1 specimen per 10 m2.
Type locality: "Bassin de I'Empcreur Nicolas", Strait of Tartary.