Abstract: High-density mountainous cities, characterized by compact spatial layouts, represent a typical urban type in China. As centers of urban public life, recreational spaces in these cities need to be effectively planned and managed in line with activity patterns and preferences of urban residents. While numerous studies have examined the vitality of recreational spaces in plain cities and their planning and optimization, the unique and complex terrain features and the limited developable land in mountainous cities create vitality patterns distinct from plain cities. Even scattered spaces such as street corners can support significant recreational activities, influenced by factors such as inadequate and unevenly distributed recreational spaces and reduced service coverage. These characteristics underscore the need to further investigate tailored to high-density mountainous environments. Using Wanzhou District, Chongqing as a case study, this paper finds that the typical access distance to recreational spaces in mountainous cities is generally within 1.5 kilometers. By comparing four representative recreational spaces in high-density mountainous cities—park green spaces, plazas, streets, and community green spaces—the paper reveals that streets and community green spaces accommodate a substantial proportion of recreational activities. Finally, by analyzing the built environment factors shaping the vitality of recreational spaces in high-density mountainous cities and by employing a geographically weighted regression model, this paper explains the difference in the influence mechanisms of vitality among the four types of recreational spaces.