The objective of the proposed work is to assess the possible effects on the shoreline dynamics of the marine energy farms. Three different coastal environments have been considered as case studies. The first area is located in the Portuguese continental nearshore at the European western coast of the Atlantic Ocean. The second in the Mediterranean Sea in the coastal environment of Sardinia Island and the third on the western side of the Black Sea in the Romanian nearshore. Besides the fact that, from a geographical point of view, the three areas targeted are located in very different zones, they represent also coastal environments with very different characteristics. A computational framework joining a spectral phase averaged wave model with a 1D parametric circulation model has been used. The numerical models are SWAN (acronym from Simulating Waves Nearshore) for the waves and NSSM (the Navy Standard Surf Model) for estimating the longshore currents. For each case study, the main characteristics of the environmental matrix have been analyzed first. Then, various transmission scenarios have been, designed considering also in each case different distances from the marine energy farm to the shoreline. A general conclusion of the proposed work is that the longshore currents are very sensitive to the presence of the marine energy farms and that is why such farms can also play an active role in coastal protection. Moreover, since it presents in parallel similar analyses for three coastal environments that have very different features, the present study provides a more comprehensive picture concerning the medium to long term impact on the shoreline dynamics of the future marine energy farms operating in the nearshore.