İDO (İstanbul Deniz Otobüsleri)

Who they are

İDO, short for İstanbul Deniz Otobüsleri ("İstanbul Sea Buses"), is the fast-ferry and car-ferry operator that links İstanbul with the southern shore of the Sea of Marmara. It was founded in 1987 by the İstanbul Metropolitan Municipality to take pressure off the city's roads. In 2011 it was privatised for 861 million US dollars, and today it is owned in equal shares by Akfen Holding and Tepe.

Akfen gives a fleet of 45 vessels: 21 sea buses, 18 car ferries, four fast ferries, one high-speed ferry and one service ship. The company says it carries about 30 million passengers and 10 million vehicles a year.

İDO runs two main types of service: high-speed passenger catamarans (the deniz otobüsleri, or "sea buses") and larger ferries that carry vehicles as well as passengers. That makes it useful for commuters, for families driving to Bursa for the weekend, and for travellers heading into Anatolia without fighting İstanbul traffic.

Network and routes

İDO's main hub is Yenikapı, on the European side of İstanbul. Its core routes are:

• Yenikapı–Bursa (Güzelyalı): fast car ferry, about 1 hour 35 minutes, with six or seven sailings a day in each direction. The terminal is at Güzelyalı in the Mudanya district, about 25 km from central Bursa, Turkey's fourth-largest city, known for its Ottoman mosques, silk bazaar and the Uludağ mountain.
• Yenikapı–Yalova: fast ferry, about 75 minutes, around eight sailings a day. Yalova is a popular weekend area with thermal spas and road links toward Bursa. İDO also sails to Yalova from Pendik on the Asian side.
• Yenikapı–Bandırma: fast car ferry, about 3 hours, two or three sailings a day. Bandırma has trains to İzmir, which makes this a useful alternative to the long drive south from İstanbul.

In summer İDO adds sailings to Marmara Island, Avşa and Çınarcık. It also runs other routes, including sea-bus sailings from Kadıköy.

Fleet and on board

İDO's sea buses are fast catamarans built for passenger volume rather than luxury. Seating is aircraft-style, with air conditioning and large windows, and there is usually a small café selling tea, coffee and snacks.

The fast car ferries are larger: vehicles drive onto the car deck and passengers sit in lounges above. The biggest carry more than 1,000 passengers and 200 vehicles. On a clear day the crossing gives fine views across the Sea of Marmara and, leaving Yenikapı, of the İstanbul skyline.

All İDO routes are domestic Turkish services, so there are no passport or visa checks on board. Carry your passport or ID as you would anywhere in Turkey.

Booking and tips

İDO tickets can be booked on the İDO website and app or at the terminal ticket offices. There are cheaper promotional fares and standard fares; in 2026 a promotional fare from Yenikapı to Bursa cost 765 TL.

For car ferry sailings, especially on Friday evenings and before public holidays, book car space several days ahead, as spaces sell out. Passenger seats are easier to find but can fill on the busiest holiday departures.

Arrive at the terminal at least 30 minutes before departure as a foot passenger, and earlier if you are taking a vehicle. Sailings can be cancelled in strong winds or fog. If the weather is bad, the Marmaray rail line and intercity buses are the fallback.