The SEAFO coral and sponge taxa guide was developed by the Spanish Oceanography Institute (lEO) and the Marine Science Faculty at the University of Vigo (Galicia, Spain). This is a simple pictorial guide to corals and sponges for use by sea-going observers in the SEAFO Convention Area (CA). The aim is to enable observers to identify general types of corals and sponges as it is rarely possible at sea to identify specimens to the species level (this often requires microscopic analysis ashore). The guide is a first edition and will be improved on the basis of feedback from observers and also as more information on corals and sponges becomes available in the SEAFO Convention Area.