Ralfsia verrucosa is a cosmopolitan species and is found in temperate waters in northern and western Europe, Mediterranean Sea, Iceland, Greenland, Canada, New England, Argentina, round the coasts of Africa, India, Japan, Korea, China, Russia, Indonesia, Australia and New Zealand.
•
Round the coasts of South Africa, Ralfsia verrucosa enjoys a mutual relationship with the limpet Scutellastra longicosta.