Climate change poses one of the biggest challenges that most countries have to face over the coming decades. The transformations in our global weather patterns are expected to bring some very adverse effects for most of the island nations that comprise the Caribbean region. These nations have been continuously identified as one of the territorial groups that are most vulnerable to climate change, while the region barely contributes to the main triggers of these changes. Caribbean island nations have many elements that hinder their individual and regional development. Climate change will aggravate those conditions while bringing new challenges to these territories, particularly in the capital cities, as these urban areas serve are the main economic, social, political and cultural centres of these nations. A good understanding of the vulnerabilities of these cities will become a critical factor for developing good adaptation measures for their respective nations. Planning can prove useful for implementing climate change adaptation strategies, particularly for cities. This research provides three main contributions to the literature on climate change and on urban planning studies. First, it expands the discussion upon the linkages between disaster risk reduction experiences and climate change adaptation practices. Second, it highlights the relevance of capital cities for evaluating climate change impacts and adaptation actions for small island territories. The third contribution is the creation of a planning tool to assess climate change vulnerabilities of Caribbean cities. These three elements will further expand the existing knowledge base related to climate change adaptation and urban planning disciplines, particularly pertaining to the Caribbean region. Caribbean cities will greatly benefit from a planning perspective that can guide their development processes in the face of climate impacts. By means of vulnerability assessments it is possible to facilitate the analysis of climate change impacts and outcomes on vulnerable areas and planners can contribute to this aspect. A planning support tool was created to aid in the development of a vulnerability assessment for small island cities in the region - the Caribbean Climate change Urban Vulnerability Index (CCUVI). Using the CCUVI, a vulnerability assessment methodology was developed, using the city of San Juan (Puerto Rico) as a case study. The results of the vulnerability assessment helped identify five different areas within the case study city that are prone to be more affected by climate change impacts. The assessment also analysed how the vulnerability conditions in these areas and in the city changed through time, exploring two distinct scenario storylines for San Juan towards 2050. A series of normative and operational recommendations emerged from the assessment process that will help planners and policymakers engage in adaptation actions to reduce the climate vulnerabilities of Caribbean small island capital cities.