AbstractThe development of international trade, supply chains and transport increases the turnover of container terminals. Changes in the port environment and the functions of terminals have created a demand for logistics solutions and value-added services. On the other hand, these changes have also influenced the port-city interface.The purpose of this paper is to present the activity of container terminals and examine how the growing turnover of container units has affected the port cities. The interaction between the latter and port terminals has been discussed. The research is based on the terminals located in Polish port cities of Gdynia and Gdańsk, which play a leading role in the development of the economy in the region.The research has shown that maritime networks have an ever-growing influence on ports and port – city relationships. On the one hand, the growth of maritime logistic services has a positive influence on the labor market and transport infrastructure, which is also used by the inhabitants. On the other hand, the increase in container cargo volume has a negative impact on urban areas through a number of negative externalities (congestion, noise, pollutant emissions, etc.). This creates a conflict in which the city has to bear the external effects of the port operations. In this context, solutions incorporating the sustainable development of both port and urban areas are essential.