A while ago, a Turkish friend of mine had had the fortune (or the misfortune?) to do his mandatory military service at the Naval Cadet School of the Turkish Navy on the island of Heybeliada, one of the Princes' Islands about an hour away by ferry from the harbour of Kabatas. While this friend constantly complained about his wasting six-months of his life performing army duties on this island, I joked that at least he got to stay on this famous holiday island for six months, all free-of-charge.
Indeed, many people from Istanbul and other parts of Turkey have to pay to spend their holidays on Heybeliada. Possibly the second most well-known island of the Princes' Islands after the crowded Buyukada, Heybeliada is much less crowded than Buyukada, even on weekends.