The goal of this diploma thesis is to research the potential of inland waterway transport in continental part of Croatia depending on its position in European shipping channel Rain – Main – Danube and which are the advantages of connection Danube and Adriatic Sea over the Port of Rijeka. Also conducted research tries to determine where Croatia is in inland waterway transport comparing to European Union. Channel Rain – Main – Danube is opportunity for Croatia because of higher traffic and trade connection with European Union. Connection of Adriatic Sea and Danube River over the Port of Rijeka it’s of great economics importance not only for the whole country, but also for the Port of Rijeka. Rijeka as city and sea port would be better connected with the hinterland, it would connect Adriatic Sea with Danube River and with Central European countries and Rijeka would become the busiest port on the Adriatic Sea.