The case is made in this paper for early and integrative public participation in planning decisions concerning proposals for major development in the coastal zone. This is perhaps easy to subscribe to in theory but much more difficult in practice. Currently the extent and timing of public involvement in such decisions varies widely. A key benefit is the legitimacy that public participation provides to the planning process and, perhaps as a result, a variety of public involvement methodologies have emerged. Important considerations include which sections of the public to involve and at what stage in the decision-making process to involve them. The multidisciplinary nature of coastal zone issues will tend to engage a wide variety of stakeholder groups who in turn will influence the topics for discussion. A major port expansion proposal in the UK is used to illustrate a range of ways in which the public can be involved. The case study also highlights that public participation is an uncertain science, and to be successful can require skilled personnel and significant resources. The paper concludes that more guidance for developers, some standardisation of public involvement, training for facilitators and a more responsible stance from some environmental pressure groups would be advantageous. The complexity of coastal decision-making, tensions between science and policy, and the inter-dependency of coastal activities mutually reinforce the view that inclusive participation is an important issue for all coastal communities.