The share and life expectancy of the ageing population are increasing. However, aged people are threatened by insufficient physical activity. Therefore, finding ways to support people to live a physically active life in older age is imperative. Digital wellness technologies represent a potential solution, but in order for such technologies to be effective, research is needed to gain a better understanding on their use among aged people. To address this need, this study investigated whether the use of a physical activity application can promote physical activity among aged people. The physical activity levels were measured at three different time points: before taking the application into use, after four months of use, and after 12 months of use. The results show a modest increase in the physical activity levels. When examining physical activity categories (based on the IPAQ-E), a participant rather shifted to a higher than to a lower physical activity category. Overall, the changes were more substantial after 12 months than after four months of use. The results suggest that physical activity applications used in everyday life have potential in promoting physical activity levels among aged people.