INTRODUCTION: The COVID-19 pandemic reduced physical activity levels and increased sedentary behavior among older adults in residential care facilities. Another effect of this crisis was that facilitating a sense of social belonging through in-person social activities, such as group exercises or communal meals, became difficult. This study examines the relationship between physical activity, sedentary behavior, and sense of social belonging in older adults. METHODS: This longitudinal study, which lasted 10 months, involved 57 older adults in residential care facilities. Participants completed the RESULTS: Participants were predominantly sedentary (7.30 h/day) and engaged in low-intensity physical activities (2.9 h/day). They did not meet the recommended 150 min/week of moderate-to-vigorous physical activity. The sense of social belonging was high, with mean scores of 6.75 ( CONCLUSION: This study underscores the importance of light physical activity and a sense of social belonging in reducing sedentary behavior among older adults in residential care facilities. By promoting social interactions and light physical activity, we can enhance the well-being of this population, especially during pandemic conditions. The study's findings should inspire future interventions to focus on these aspects, thereby improving health outcomes in residential care facilities for older adults.