In the face of current global challenges and trends, such as climate change, biodiversity loss, and urban health, this article explores the necessity and opportunity of redeveloping school outdoor spaces to create healthy, productive, and climate-adaptive environments. Due to the environmental crisis, cities and urban spaces will be increasingly exposed to heat waves that negatively affect our physical and mental health. In particular, schoolyards present important urban spaces that are exposed to the effects of climate change and offer an opportunity for redevelopment, not only in terms of climate adaptation but also in terms of creating spaces for education, socialisation, and recreation. Currently, the schoolyards in Italy are often poorly maintained and underutilised, with few or no amenities for their users. Often, these areas consist of large, paved areas that, in some cases, are absent of any vegetation, contributing to elevated outdoor temperatures, reducing outdoor comfort, and lack of space for recreation and physical activity. The paper explores the potential of redeveloping schoolyards through a case study of two secondary schools in Florence (Italy), developed in the frame of the FIABA research, to transform underutilised spaces into healthy, sustainable, and attractive places. Both qualitative (questionnaires, co-creation workshops with students) and quantitative methods (environmental assessment, microclimatic simulations) have been applied for each case study, followed by design projects and evaluation with the ENVI-met software to verify the proposed solutions’ efficiency in improving outdoor comfort indicators. The results show an improvement in outdoor comfort in both cases due to the integration of the vegetation, such as green areas, shrubs, and trees, and due to the change of the paved materials.