The role of commercial and naval port evolution in the growth of coastal zone cultural heritage is outlined and problems of heritage sustainability are identified. It is proposed that these problems may be related not only to the issue of heritage conservation but also to the difficulties of identifying appropriate new uses that will secure the long-term economic viability of the port system’s patrimony. The conservation issue is explored through a case study of cultural heritage loss in the UK’s South Wales coal ports. Issues relating to economic sustainability are examined with respect to a defunct, yet architecturally outstanding, naval facility, the Royal William Yard, Plymouth, UK. It is argued that both problems can be better understood with reference to clusters of interacting and controlling ‘environments’ within which the cultural heritage is set. It is concluded that coastal zone management must recognise the challenges posed by such ‘environments’ if effective strategies to secure the future of port-based cultural heritage are to be devised. It is also suggested that the scale and complexity of the challenges are such that there is a leadership role in this sphere for international organisations such as the European Union.