American tourists need a 90-day sticker visa for visiting turkey. This is available at the port of entry for $20 cash as of August 2010 and must be obtained before entering passport control. Those visiting longer or for different reasons, e.g., diplomatic purposes, must obtain a visa from a Turkish embassy or consulate.
Travelers transferring to Turkish domestic flights from international destinations require the appropriate visa stamps before boarding the domestic airline. Otherwise, they may be detained when they try to leave Turkey.
Those arriving by cruise ship for a day trip do not require a visa if not staying overnight.
