There are car ferry services operating at all hours of the day between Gebze Eskihisar and Yalova Topçular. In Kocaeli, sea transportation is provided on 4 different lines connecting the two sides of the Izmit Gulf. The passenger ferry is used on the İzmit-Karamürsel line, and the passenger engine is used on the İzmit-Değirmendere, Gölcük-Değirmendere and Karamürsel-Hereke lines.