Deniz Cruise & Ferry Lines (“Denizline“) used to operate the car ferries m/v Samsun and m/v Ankara on overnight (24-hour) voyages between Istanbul‘s Sarayburnu (Seraglio Point) dock and Bodrum on Turkey’s Aegean coast.
This service was suspended in 2009. It is not operating.
So far as I know, there are no ferries along the Turkish coast from one Turkish port to another.
However, these ferry services are in operation:
Ferries across the Sea of Marmara
Ferries Turkish coast <—> Greek Aegean islands
Ferries from Turkish ports to Northern (Turkish) Cyprus
For international ferry services between Turkey and Athens, Greece, and Italy, go to Feribot.net:
|Turkey—Greek Islands Ferries|