The study aimed to enhance young children's knowledge of healthy eating, active play and environmental sustainability through play-based activities developed by nursery educators in Crete, Greece. Intervention group children received 4-6 weeks of curriculum activities, and their knowledge about healthy eating, active play and sustainability concepts was measured before, post-curriculum and 3-months after the intervention. Children's eating or physical activity habits were measured at the same time points. The intervention group significantly increased its knowledge about the connection between healthy living and sustainability, sustained high fruit and vegetable intake immediately post intervention and increased levels of physical activity 3-months post intervention, when compared to the control group. The findings highlight that young children can build their knowledge of health and sustainability concepts, and make more informed choices about healthy eating and physical activity. The preschool setting can play a role in health promotion and develop much-needed environmental consciousness among young children.