Climate Change Adaptation (CCA) has become a vital measure within every nation due to the significant impacts posed by climate change on Critical Infrastructures (CIs) and human lives. Despite scholars' identification of possible impacts on CIs, a lack of consideration for CCA measures to mitigate these impacts can be observed. This study aims to identify and prioritize CCA measures in the assets and infrastructure of critical sectors; electricity, transportation, and water supply considering Sri Lanka as a case study. The present study employed an Analytical Hierarchical Process (AHP) to prioritize CCA measures of these three infrastructure sectors as a system considering their interconnected and systematic nature. The prioritization process was informed by 42 open-ended expert interviews, and these interviews were also instrumental in validating the criteria used to evaluate the CCA measures. The study identified and discussed several CCA measures for different stages of the infrastructure life cycle, including planning, design and construction, and maintenance and retrofitting. The CCA measures were prioritized based on eight criteria obtained from a detailed review analysis. The results revealed that an asset management system at the planning stage is the most significant CCA measure for CIs. Furthermore, the study emphasizes that proper planning of evacuation routes, consideration of operational loads imposed by climate change, and nature-based solutions are significant CCA measures that need to be incorporated during infrastructure development. The outcome from this study provides insights for built environment professionals to adapt infrastructures to climate change. Additionally, the results of the study can be integrated into the rules and regulations of the developing countries to enhance climate resilience within the built environment.