Maritime transport is one of the most affordable and the cheapest in the transport sector. It is often the only way of transporting passengers and goods that have a strong impact on the development of seaports as well as their infrastructure and superstructure. On the basis of realized freight and passenger traffic, the seaport is divided into important ports both in Croatia and in Europe. Due to the above mentioned facts, this paper describes the significant European freight corridors Rotterdam, Hamburg, Antwerp, Trst, Gioia Tauro, Genoa, and significant passenger ports Barcelona, Helsinki and Piraeus. Of the major and important ports in the Republic of Croatia, Rijeka, Split and Dubrovnik are described. In addition to the individual descriptions of significant European cargo and passenger ports, as well as important ports in the Republic of Croatia, the work will describe the structure, superstructure, technical equipment as well as the statistical data that are classified into important European and Croatian ports.