Development of the river sea transport is directly related to the characteristics of waterway network which enables navigation between river basins and seas. Inland waterways in Serbia belong to the Danube navigational system. There are two navigational directions: Danube East and Danube West. River-sea transport can be directly established in these directions between the Serbian international ports on the Danube (Apatin, Novi Sad, Belgrade, Pancevo, Smederevo and Prahovo). Development of the Pan-European Corridor VII and the River Danube-Black Sea and Danube-Rhine-Main region would allow not only in Serbia but also in neighbouring states and all over Europe connection with the sea. In this paper the technical and exploitation characteristics of the river Danube will be analysed in terms of the navigation of various river and sea vessels with different exploitation characteristics.