Abstract Oceanographic and diving surveys were conducted at the largest SPA of Mediterranean basin, Datca Bozburun Specially Protected Area, in 2002-2004 periods by the Institute of Marine Sciences and Management of Istanbul University in order to determine marine biodiversity, distribution and condition of endangared or protected species and to make suggestions on management of coastal areas. Studies revealed in detection of 536 species of fauna and flora. Some problems were detected in some areas particularly around settlements. Despite of the wide coverage of Posidonia oceanica beds at the region, the invasion and distribution of Caulerpa species point out severity of problems.