Background: In older adults, mobility is important for maintaining their independence and quality of life, and it influences their physical, cognitive, and social health. This study aimed to identify the physical and psychosocial factors that affected the mobility of community-dwelling older adults, aged 65 years or older, who were socially isolated during the coronavirus disease 2019 (COVID-19) pandemic due to stay-at-home policies. Methods: The participants in this study were 214 community-dwelling older adults in Korea, and a cross-sectional survey was conducted from December 2020 to January 2021. Variables included participants’ general characteristics, mobility, sitting time, depression, social support, and cognitive function. Results: Multiple linear regression analysis showed that the factors influencing older adults’ mobility during the COVID-19 pandemic were depression (β=-0.29, p <.001), age (65–74 years old) (β = 0.19, p =.002), a lower level of education (β=-0.17, p =.006), two or more comorbidities (β=-0.18, p =.001), sitting time (β=-0.17, p =.004), and the ability to drive a vehicle (β = 0.14, p =.017). Conclusions: Home healthcare interventions are needed to limit psychosocial issues and improve mobility for older adults who had limited mobility during the COVID-19 pandemic.