Ports have high economic importance, but they are at the same time a significant source of pollution, originating either from ship cargo or from waste produced on board ships. The concept of a green port applies as a new paradigm that endeavours to align port activities with environmental and social matters without jeopardizing economic growth and is as such a synonym for sustainable ports. Along with indispensable introducing of regular sea sampling in the port, new available technologies such as remote sensing should be applied in order to improve water quality monitoring and achieve a more efficient control of marine areas, thus enhancing ports sustainability.  The paper provides an overview of available tools for the analysis of seawater quality and elaborates the potential of remote sensing of the quality of marine environment in the Port of Rijeka, the major port in the Republic of Croatia.