The importance of sustained physical activity in healthy aging is well established. To achieve sustained physical activity and exercise, related self-efficacy is important. Hence, solutions to promote self-efficacy for exercise among aged people are urgently needed. Digital wellness technologies provide a potential solution, but research on their potential to promote selfefficacy for exercise is scarce and more research is needed. To address this need, this study investigates how effective is the use of a physical activity application in promoting self-efficacy for exercise among aged people. Self-efficacy levels were compared between three different time points: before taking the application into use and after 4 and 12 months of use. The results suggest that physical activity application use can be effective in promoting self-efficacy for exercise among aged people as there was an improvement in most of the self-efficacy items as well as in total self-efficacy already after 4 months of use and this improvement was sustained after 12 months of use.