Onchidoris sparsa was described from England and it is currently known from the European coasts of the North Atlantic,Norway, Orkney and Sweden south to the northern coast of Spain. This species feeds exclusively on bryozoans ( Cellepora pumicosa and Porella concinna.).
The body is translucent brownish with scattered light and dark brown patches. The mantle with many small rounded tubercles.
Similar Species are Onchidoris inconspicua and Onchidoris depressa.