Unsupervised outdoor activity plays an important role in children's personal and social development, and their ability to manage the urban environment. However, children now have less unsupervised outdoor activity than in the past, and less physical activity overall. They travel shorter distances and are less likely to walk or ride to school on their own. The decline in unsupervised activity reflects, in part, parents' anxiety about risks such as traffic accidents, stranger danger and bullying, but parental concerns themselves could be seen to reflect a more general shift in thinking at the level of public policy. This article reports on recent research on the impact that changing conceptions of risk have had on children's independent mobility, and considers implications for educators.