Background: The lack of physical activity because of restrictions from the pandemic has increased interest in the deterioration of mental and physical health. This is the first study in Korea to investigate how PARTICIPATION in physical activity is correlated with SUBJECTIVE well-being among Koreans in the early stages of the COVID-19 pandemic. Methods: The survey was conducted among those aged >13 years, from August 24 to September 7, 2020. The process included self-reported surveys, telephone surveys, and face-to-face household interviews,11, 604 people (men=7, 758 and women=3, 846) participated. Frequency, correlation, and one-way analysis of variance were performed to identify differences between age and sex groups according to the physical activity level, while post-hoc Scheffe tests to examine between-group differences when significant results were observed. Results: Statistically significant correlations were observed between life satisfaction, living environment satis-faction, and levels of happiness and anxiety based on sex and age (P<0. 05). There were significant differences between frequency and time spent on physical activity and SUBJECTIVE well-being according to sex and age (P<0. 05). Conclusion: The study results are highly generalizable considering the analysis of a large-scale sample within a big area in Korea. The findings emphasize that SUBJECTIVE well-being is influenced by sex, age, frequency, and time spent engaged in physical activity. Such basic data can be helpful for establishing policies related to physi-cal activity.