EU policy geared towards the sustainable development of European coastal areas has incorporated Integrated Coastal Zone Management (ICZM) as one of its primary mechanisms to achieve its goal. However, critical shortcomings in the ICZM paradigm have emerged. In particular, incoherence in the European Commission’s ICZM principles with respect to local and strategic objectives remains an issue. Additionally, a lack of scientific certainty about environmental processes when determining the environmental pros and cons of alternative coastal-management decisions undermines environmentally protective decisions that may otherwise hinder local regional development. With these issues in mind, a Biodiversity Portfolio Analysis (BPA) is applied to Iarras Aithneach, a peninsula on the west coast of Ireland, to test its suitability as tool for ICZM. In addition, the paper uses the BPA methodology to explore the contrast between scientific/strategic and local attitudes towards the management of a coastal area of environmental importance. Pronounced differences between the two are found and the implications for both BPA and ICZM are discussed. The spatial and participatory nature of the BPA process and the explicit treatment of risk the framework exhibits suggest there is scope for it to become a useful tool for ICZM. It also has the potential to act as a routine way of quantifying the “attitude gap” between the scientific community and the local community when managing a unique coastal area.