The mainstreaming of climate change adaptation (CCA) is increasingly popular because it integrates both adaptation and sustainable development goals. Although research interest in mainstreaming CCA is growing, there is limited information on its practical application at the local level, particularly in relation to the barriers to the effective operationalization of the approach. Consequently, this paper examines the challenges in mainstreaming CCA into local land use plans in Albay, Philippines. Using a modified version of Ostrom’s Institutional Analysis and Development framework, the conditions surrounding the challenges were identified and assessed. These challenges are characterized as the factors that depict the information, institutional, and resource capacities of systems; hence, they are the factors that affect the effective operationalization of mainstreaming CCA. These challenges were then converted into quantitative “mainstreaming indicators”. Data were collected from a survey conducted among the key players in local land use planning and experts in mainstreaming CCA. A scorecard approach was applied to quantify the respondents’ answers. The results highlighted the “institutional issues” indicator as the primary barrier in operationalizing the approach, while “availability” and “access to information” were assessed as second-level barriers. Conversely, the “leadership” indicator was evaluated as an opportunity for local mainstreaming due to the existence of a climate change champion in Albay. This paper suggests that the: (1) challenges exist in a certain spectrum, in which they can be either barriers or opportunities for mainstreaming; (2) barriers can be classified according to varying degrees of severity; (3) challenges themselves are inter-linked; and (4) barriers can be overcome and transcend into opportunities for mainstreaming CCA.