Please check the ferry timetables on the websites.
Ticket of the regular ferry to the Princes' Islands: 3.50 TL with IstanbulCard, 5 TL with token
Fast ferry tickets: from Kabataş (European side): 7.10 TL with IstanbulCard, 9 TL with token
From Bostancı (Asian side): 4.25 TL with IstanbulCard, 5.50 TL with token
Wikipedia https://ru.wikipedia.org/wiki/Хейбелиада
Ferry Timetable http://en.sehirhatlari.istanbul/en/timetable/besiktas-heybeliada-buyukada-3487.html
Координаты 40°52'30.72" N 29°5'24.76" E
