Background: Choose to Move is one of few scaled-up health-promoting interventions for older adults. The authors evaluated whether Choose to Move participants maintained their intervention-related gains in physical activity (PA), mobility, and social connectedness 12 months after the intervention ended. Methods: The authors assessed PA, mobility, loneliness, social isolation, and muscle strength via questionnaire and objective measures in 235 older adults at 0 months (baseline), 6 months (end of intervention), and 18 months (12-months postintervention). The authors fitted linear mixed models to examine the change in each outcome from 6 to 18 months (primary objective) and 0 to 18 months (secondary objective) and reported by age group (60–74 and ≥75 y). Results: In younger participants, PA decreased between 6 and 18 months, but remained significantly higher than at baseline. Intervention-related benefits in loneliness, social isolation, mobility, and muscle strength were maintained between 6 and 18 months in the younger participants. Older participants maintained their intervention benefits in loneliness, mobility, and muscle strength. When compared with baseline values, PA levels in older participants were unchanged, whereas social isolation increased. Conclusions: Older adults maintained some, but not all, health benefits of Choose to Move 12 months after the intervention ended. Long-term commitments are needed to deliver effective health-promoting interventions for older adults if benefits are to be maintained.