Marine and coastal areas are under significant pressures due to the intense concentration of population and activities that often drive in conflicts. Marine spatial plans need to be enacted and implemented, considering the particularities of marine areas, the existing and future activities and uses and their environmental impact and the land–sea interaction. The paper main question concerns the emerge of uses conflicts on marine and coastal areas, with significant uses accumulation. Crete Island is used as the case study. It studied the conflicts or synergies of marine uses as well as their spatial and quantitative representation.