Because this species attains a maximum size of 14 mm, it is relatively large for an Opalia. This species ranges from Japan, where it was originally described, to Natal, South Africa. There are approximately 8 strongly convex whorls with 16-18 axial ribs with sloping sides per whorl. The suture is strongly crenulated. No varices are present. Microscopic spiral striae can be seen between the ribs. A basal cord is present. It is white in color, the outer lip is thickened and the aperture is oval. It can be distinguished from O. methoria by the larger number of ribs and the crenulated suture.