Coastal zones represent a small part of the area and volume of the oceans. However, their importance as a land-sea interface is enormous. Over 60% of human population lives within 60 km of the sea, and coastal zones guarantee several essential services to humanity. These ecosystems work as a convergence mechanism of all human actions in adjacent watersheds, being necessary to be considered in their management, in accordance to the Water Framework Directive spirit. Several integrated coastal management tools are presented in this paper, developed for an European project using as an example Parque Natural da Ria Formosa (south of Portugal). These tools include an hydrological model, a coastal ecological model, a geographic information system, and a decision support system. The hydrological model predicts water flow and water quality to be input to the ecological model of the lagoon system. The decision support system is being developed to integrate the environmental and social-economic information. The end-users, with management responsibilities, allow an information interchange between researchers and decision makers.