This study investigated whether strength, balance, body mass index, falls self-efficacy, activity levels, self-rated health, and participation in a multicomponent exercise intervention could predict physical activity levels after 5 months of self-quarantine due to the COVID-19 pandemic. This study included baseline data of 200 community-dwelling older adults (79% women, 21% men) with a mean age of 72 years who participated in a randomized controlled trial investigating a multicomponent exercise program, with 7-month follow-up survey data of their physical activity levels. The results showed significant associations with the activity levels at the 7-month follow-up. The activity levels (odds ratio (OR): 2.83, 95% CI: 1.20–6.71), the self-rated health score (2.80, 1.42–5.53), and being allocated to a specific multicomponent group-based exercise program (2.04, 1.04–4.00) showed a significant association with the activity habits at the 7-month follow-up. As this study suggests, besides the physical activity levels and the self-rated health score, participation in a high challenge multicomponent exercise program was significantly associated with physical activity levels at the 7-month follow-up. This study indicates that a relatively short multicomponent group exercise program (6–9 weeks) can motivate individuals to sustain their own training and activity levels even several months after the program has been paused or terminated. Identifying older adults’ physical activity levels and self-rated health scores and prescribing multicomponent group-based exercise programs to promote sustained physical activity habits may be a successful alternative to provide for older adults in the future.