The seabuses zoom to docks in the city center and also across the Sea of Marmara to its southern shore and islands, with most service being during the morning and evening rush hours.
Because of their speed, catamarans run the longer routes in Istanbul's maritime transport system, leaving the shorter routes to the comfy, traditional Şehir Hatları ferryboats and the smaller TurYol and Dentur Avrasya ferries.
You may not find the İDO (pronounced "EE-doh") seabuses very useful for travel within Istanbul, as they don't serve many touristic destinations, but they are the best way to reach other cities across the Sea of Marmara. More...
The principal fast catamaran dock is the Yenikapı Feribot Terminalı on the Sea of Marmara shore south of Aksaray Square. Yenikapı serves both seabuses and fast car ferries (hızlı feribot), and is a station on the Marmaray cross-Bosphorus train line.
—by Tom Brosnahan
|Yenikapı Ferry Terminal|