Zoanthus sansibaricus is a colonial zoantharian (family Zoanthidae) distributed in shallow reef environments of the western Indian Ocean and East African coast, including around Zanzibar (Sansibar) from which it takes its name, forming encrusting mats on reef rock and dead coral substrates. The species is part of the diverse Indo-Pacific zoanthid fauna and maintains photosymbiotic relationships with Symbiodiniaceae in the shallow, well-lit reef environments it inhabits. Genomic data have been generated for this species and are available in public databases, enabling comparative studies of cnidarian evolution and ecology.