The Western Indian Ocean (WIO) has been identified as a global hotspot for chondrichthyan diversity, with 130 shark, 86 batoid (wedgefishes, skates and rays) and 11 chimaera species identified to date. The WIO is one of four global hotspots for chondrichthyan evolutionary distinctiveness, giving the region’s chondrichthyans a high irreplaceability index, and highlighting the need for their conservation.