Cycling during youth is characterized in many countries by two trends: its decline over the course of several decades (termed the generation effect) and its decline over the life course of individuals (the age effect). This paper addresses the age effect through a survey carried out among young people aged 12–20 (n = 1,358) in a Swiss city. It goes beyond the cyclist/non-cyclist dichotomy and identifies several cases in terms of skills (ability to ride a bike), access (ownership of a bike), and uses (reasons for and frequency of cycling). While most young people (98%) learned how to ride a bike as a child, an important minority do not continue cycling beyond childhood. Among those who continue, the use of the bike often changes over time to become less utilitarian and more recreational and occasional. The main determinants explaining cycling practices among young people are socialization (the parents’ cycling practices and level of education), gender, and the spaces of everyday life (place of residence and school). The results point to several levers to foster cycling among young people, to anchor sustainable mobility practices for years to come.