This paper explores patterns of increased/ decreased physical activity, sedentary and sleep behaviours among Canadian children and youth years during the COVID-19 pandemic, and looks at how these changes are associated with the built environment. Two groups were identified who were primarily distinguished by increased versus decreased outdoor activity. For children, living in a house (vs. apartments) encouraged outdoor activities; proximity to major streets was a barrier. For youth, low dwelling density, and access to parks in high-density neighbourhoods had positive effects