Physical activity is important to children’s health and development. However, few Hong Kong children met activity guidelines proposed by the World Health Organization. The Fun to Move@JC, which began in 2017, is a school-based project designed to increase physical activity of children. By enhancing home school cooperation and applying state-of-the-art technology, the project aims to improve the quality and quantity of support children receive from their schools and families. In this webinar, we will discuss how COVID-19 influenced children’s and parents’ physical activity and health, and also how project initiatives were adapted to counter the effects of the pandemic. Our findings have important implications in terms of physical activity promotional strategies in the Greater Bay Area. First, supportive policies at school or governmental levels will benefit children’s activity behaviours. Engagement of parents through home school cooperation is also effective in increasing physical activity in individuals and co-activity between children and parents; the latter is associated with beneficial outcomes such as better parent-child relationships. Finally, appropriate use of technology allows activity levels to be monitored by users and policymakers efficiently, and hence timely and efficient interventions could be designed.