Portugal's seaport communities are undergoing substantial change. Once protected by the nation's closed economy and restrictions to cultural adaptation, they are now required to face increased competition, shifting markets, the need for increased efficiency and for new infrastructural systems. In addition to all this, the uses of those seaports need to be examined: will they be centers for fishing, freight activities or have mainly tourist functions? Clearly, the Portuguese seaports of tomorrow will not be the same as they are today. While seaport planners struggle with these issues, it is essential that they identify, protect and enhance those elements of the harbors that are important to the nation's patrimony. Indeed, too often, countries in the midst of rapid change ignore those elements and frequently regret their actions at a later time. This paper is a call for a set of actions to insure that these special places are protected. This paper is based on our experience in harbor planning in Portugal and in the United States. In Portugal we have undertaken research on port development in Oporto, Viana do Castelo, Aveiro, Setubal and Figueira da Foz. In the United States we have research port development in Providence, Gloucester, New Bedford, Fall River and more than ten small port communities. In addition, we have also conducted library and archival research on harbor development, and interviewed key port development planners on both sides of the Atlantic.