This study aims to implement a new family-based health behavior community program to increase time spent outdoors and physical activity among Singapore children aged 6 to 12 years in a 1-year randomized clinical trial. 300 children from 250 families will be randomly assigned to either a family-based intervention or no intervention. The family-based intervention comprises structured weekend outdoor activities organized by National Parks and incentives for children to wear a pedometer and increase their daily steps. Families who meet their monthly step and outdoor activity goals will receive a range of prizes and incentives. Both groups will receive brochures on the National Myopia Prevention Program and physical activity. The success of the intervention will be evaluated through light meters, 7-day outdoor diaries, questionnaires documenting outdoor time and myopia; as well as pedometer steps, walking tests, and body mass index. A community-based intervention will be developed to improve the health of Singapore children by increasing outdoor time and physical activity to prevent myopia and obesity.