Seaports are an important factor in the development of many economic activities, and thus effect the development of the economy of the country in which they are located, as well as the development of the economy if the wider regional area. Maritime transport is considered to be the most economical branch of transport, so the majority of foreign trade in the world goes by sea, which makes ports unavoidable locations for trade in the world. Ports reduce the cost of transport, contribute to employment at the regional level and encourage the development of port and other activities. Economic, sociological and technological development encourages ports to improve their business and adapt to market demands, so that they can be as competitive as possible and to attract as many new users as possible, thus contributing to the development of the region. The primary goal of the thesis is to investigate and explain the multiplicative effects of the development of ports open to public transport on economic growth. This is dealt with in the most detail through the examples of the ports of Ploče and Gioia Tauro. It is on these examples that the real impact of seaports on the growth and development of regional economies is proven.