Danube
The Danube flows through many cities, including four national capitals (shown below in bold), more than any other river in the world. Ordered from the source to the mouth they are:
The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania and by river ships to Kelheim, Bavaria, Germany; smaller craft can navigate further upstream to Ulm, Württemberg, Germany. About 60 of its tributaries are also navigable.
Sava
The restricted draft and fairway is compounded with meandering of the river's course—limiting length of vessels—and low bridge clearance. Further problems are incurred through poor transport infrastructure along the route, including poor navigation markings, and presence of sunken vessels and unexploded munitions. Navigation along further of the river upstream to Rugvica near Zagreb is possible for vessels with tonnage below , and the section of the river belongs to the AGN's Category II. There are plans for restoration of the Category IV compliant waterway downstream of Sisak and betterment of navigation infrastructure between Sisak and Rugvica, as well as upgrading of the waterway between Brčko and Belgrade to Category Va, matching that of the Danube, with uninterrupted navigation through the year. The plan is planned to be supported by the European Union and , an agreement to implement the plan was signed by Bosnia-Herzegovina and Croatia, while Serbia is invited to join the project. The plan aims to increase safety and volume of river transport, which declined by about 70% since the breakup of Yugoslavia, largely because of poor maintenance of the route. The ISRBC is tasked with establishment of an international regime of navigation on the river since 2005.