Has anyone visited Princes Island off the coast of Istanbul? We are arriving a few days ahead of our tour and thought this might be an interesting adventure. Is it a ferry ride from Istanbul? Any input would be greatly appreciated.
There are 9 islands but I suggest you to visit the main&best one: Büyükada (it means Grand Island)
The island is quite big so you can't walk to everywhere. You can make a Phaeton tour or rent a bike. If you would like to go to beach, you can take a small boat from the pier of Büyükada. (The water is always dirty, don't expect to swim but you can go there for sunbathing anyway) Taking boat is free but you need to pay for the entrance to the beach: It was 20 TL (~ $10) per person last year.
How to go to Büyükada or the other islands? You can take ferries from Eminönü&Kabataş (European side) or Kadıköy&Bostancı(Asian side). There are also small boats from the same spots. Price: If you buy tokens, it's 5 TL(~$2,50) but if you have a Istanbulkart it's 3,50 TL(~ $1,75)
It takes 1 and a half hour from Eminönü, Kabataş(more than this, because it makes a stop in Kadıköy, Asian side) and Kadıköy, it takes 45-50 mins from Bostancı to Büyükada.
Do not even think about going there on a weekend because the islands are too crowded and messy.
Source: An Istanbulite (born&bred)
Since we haven't researched these islands yet, we don't have any suggestions on what's best. The advice in this thread looks good. I would also consider a Lonely Planet guidebook as well. Sorry we couldn't help more.