The island of Kos in Greece is just off the coast of Bodrum in Turkey. There are fast ferry connection between Kos and Bodrum. Thus, it is ideal for a day trip. Visitors traveling between Greece and Turkey by ferry have the option of purchasing a single one-way ticket, a same-day round-trip ticket, or a round-trip ticket with an open return date. You can get a return ticket same day from €22 and €15 for a child (price level in 2014).
There is no visa required for your entry into Greece or for short time excursions from Turkey with a duration under 30 days, but check to be sure: Visa Information For Foreigners in Turkey.
There are daily ferryboat service between Kos and Bodrum and the duration takes between 15 and 60 min depending on the type of vessel. Be aware that you must be at the location one hour before departure, and there can be very queues on arrival to the passport control on both sides, so remember to put that into your scheduling.
Kos in Greece
The island of Kos measures 40 by 8 kilometres and is only located 4 km from the coast of Bodrum, Turkey.
Kos has a population of 33,388. The biggest town and seat of the municipality is Kos Town. You will find the ferries from/to Turkey in Kos Town.
Read more about Kos here: