Ferries in Istanbul are a mode of public transportation within and surrounding the city of Istanbul, Turkey. There are three major ferry operators in the city: the municipally owned Şehir Hatları, which operates traditional vapurs; the privately operated İstanbul Deniz Otobüsleri (İDO), which operates high-speed urban and intercity services, and the privately owned Turyol which operates mostly urban services.

Public transport in Istanbul comprises a bus network, various rail systems, funiculars, and maritime services to serve the more than 15 million inhabitants of the city spread over an area of 5,712 km2.