Abstract: Some European regions are experiencing unprecedented impacts due to climate change. The islands of the Outermost Regions are also being affected by this phenomenon. When these islands have a higher level of functional complexity, climate change increases the difficulty of defining their urban and regional planning tools. A comparative analysis of the characteristics of these islands (comparing land use and demographic density) and a review of the efficacy of planning tools for incorporating climate change adaptation has been developed in order to understand the transformations produced in the regulatory frameworks. Through the case studies of Gran Canaria (Spain) and Reunion Island (France), which show high levels of urban and peri-urban land use pressure, the paper focuses on analysing the degree of mainstreaming adaptation strategies, as key elements for land use planning in a context of climate change. Results show a dysfunction between adaptation needs and the incorporation of the climatic issue in land use management. Insular planning tools do not generally consider climate change adaptation and excessive top-down management is observed in the decision-making process. This paper contributes new case studies to the literature, comparing two non-sovereign European islands, and reviews the regulatory framework on adaptation in insular contexts related to climate change.