Aim: The main aim of this study was to examine leisure engagement and loneliness among older adults before and during the COVID-19 pandemic by analysing population-based data from western Finland and northern Sweden. Methods: The data originated from the Gerontological Regional Database (GERDA) postal questionnaire study conducted in 2016 (n=7996) and 2021 (n=8148) among older adults aged 65, 70, 75, 80 and 85 years. Associations between loneliness and leisure engagement were analysed using logistic regression. Results: In total, 10% and 9% of the older adults reported loneliness in 2016 and 2021, respectively. The results showed that a lack of engagement in socialising and pleasure was independently associated with loneliness in both study years, while a lack of engagement in cultural activities was associated with loneliness in 2016 only. In 2021, the likelihood of experiencing loneliness was higher in the Finnish region than in the Swedish region. In addition, those reporting a decrease in hobby and socialising leisure activities due to the COVID-19 pandemic were more likely to report loneliness. Conclusions: Most leisure activities decreased during the pandemic, suggesting an increase in social isolation. However, this did not reflect an increase in loneliness in the studied regions. The evidence suggests that leisure engagement, especially socialising activities, continued to be important for well-being among older adults during the pandemic. Further, loneliness was affected by contextual factors as well as individual-level characteristics. Thus, according to the measures reported here, the pandemic seemed to have a slightly weakened well-being impact in Finland.