This study aims to present a strategic direction in revitalizing tourist destinations using the concept of “functional adaptation” and applying it to the Yedang National Tourism Resort located in Yesan-gun in Chungcheungnam-do, which is losing its functionality as a tourist attraction. The term “functional adaptation” as used in this study refers to applying an intervention to natural changes while maintaining the existing functions, adapting them to changing tourism marketing paradigms. First, problems and potential functions were derived from relevant literature, on-site surveys, and in-depth interviews with insiders from the target resort. Indicators of revitalizing tourist destinations were then preselected from the reviewed literature data, and the final function-adaptive activation indicators were developed after subjecting the preselected preliminary indicators to reliability testing through a Likert-scale questionnaire survey with experts. Finally, the analytic hierarchy process (AHP) was employed for an importance-analysis of individual elements of the developed indicators. The analyses revealed the tourism resort’s “storytelling development” as having the highest importance, followed by “transport connectivity”, and “amusement/leisure programs offered”. The function-adaptive activation indicators developed in this study were applied to the Yedang National Tourism Resort for the importance-analysis of its functions, but the generalizability in applying the proposed indicators to other tourist sites has not yet been established. The findings of this study are expected to serve as an input for setting up strategies for tourist site revitalization in future in-depth research.