The Princes' Islands, officially just Adalar; alternatively the Princes' Archipelago; is an archipelago off the coast of Istanbul, Turkey, in the Sea of Marmara.
The islands constitute the Adalar district of Istanbul Province. With a total land area of 15.85 km2, it is the eighth smallest district in Istanbul, and with a permanent population of 16,372, it is by far the least populous district in Istanbul.They consist of four larger islands, Büyükada with an area of 5.46 km2, Heybeliada with an area of 2.4 km2, Burgazada with an area of 1.5 km2, Kınalıada with an area of 1.3 km2, and five much smaller ones, Sedef Adası with an area of 0.157 km2, Yassıada with an area of 0.05 km2, Sivriada with an area of 0.4 km2, Kaşık Adası with an area of 0.6 km2, and Tavşan Adası with an area of 0.4 km2.
Wikipedia https://en.wikipedia.org/wiki/Princes'_Islands
Official Website https://www.geziyerler.com/adalar-gezilecek-yerler
Coordinates 40°52'26.997" N 29°7'45.57" E