Saint Sirikos Island, also known as Saint Cyril Island, is a Bulgarian island in the Black Sea, located 150 meters from Sozopol, with an area of about 0.08 square kilometers and a height of 15 meters. Unlike most other Bulgarian Black Sea islands, its entire infrastructure is established . The island was named after the medieval monastery of Saints Sirius and Goleta, and its ruins still exist to this day. The island has also become a center for international marine tourism, and a national cultural monument whose heritage is preserved and provided with new buildings to keep pace with development.