St. Thomas Island ( Bulgarian : Тома , ostrov sv. Toma ) or Zmiyski ostrov (Змийски остров, Snake island )), is a Bulgarian island in the Black Sea , 15 kilometers (9 miles) south of Sozopol. It has an area of 0.012 square kilometers (2.97 acres) and is one of a few places in Bulgaria where wild cacti grow. The Opuntia cacti were brought from the Botanical Garden in Bratislava , Slovakia and planted by the Royal Botanist Ivan Bureshon the orders of Tsar Boris III in 1933. They have most of the island since then.  
St. Ivan Island ( Bulgarian : . Остров св Иван , . Ostrov sv Ivan ) is the Largest Bulgarian island in the Black Sea , with an area of 0.66 square kilometers (0.25 square miles).  It lies off the Bulgarian Black Sea Coast near Sozopol , a town with a rich history and a popular tourist place, and is separated by several hundred meters from the small neighboring St. Peter Island . Standing at 33 meters (108 feet) above sea level , it is also the highest of the Bulgarian sea islands. It lies 920 meters (0.57 miles) from the Stolets peninsula, Sozopol’s Old Town.
St. Cyricus Island ( Bulgarian : . Остров св Кирик , ostrov sv Kirik. ), Also Known As St. Cyril Island or Sts. Quiricus and Julietta Island is a Bulgarian island in the Black Sea , 150 meters (490 feet) from Sozopol ‘s Stolets peninsula. It has an area of about 0.08 square kilometers (0.03 square miles)  and a height of 15 meters (49 feet). The island is connected to the continent by a road and a breakwater . Unlike most other Bulgarian Black Sea islands, its infrastructure is completely set up.
St. Anastasia Island ( Bulgarian : Астров св. Анастасия , ostrov Sv. Anastasiya , formerly called Bolshevik Island , остров Болшевик) is a Bulgarian islet in the Black Sea . It is located 1.5 km off the coast near Chernomorets , at 12 meters above sea level, and covers a territory of one hectare. It is the only inhabited island of the Bulgarian Black Sea Coast .