<p>Policymakers often cite positive outcomes from early childcare programmes, yet the evidence is mixed and largely based on enrolment effects for children aged 3–5. This study examines the intensity of childcare, measured in hours, for children under age 3, focusing on impacts on non-cognitive skills from ages 3 to 14. Despite policy focus on subsidised childcare hours, this question has received little attention. Using a nationally representative English birth cohort and an instrumental variables approach based on the probability of the mother working shift work and having unpredictable hours during pregnancy, this research finds that increasing hours in formal childcare has an initial positive impact on non-cognitive skills that persists over time. I also find that disadvantaged children appear to benefit more, suggesting that expanded access to longer childcare hours could reduce early inequalities. Findings are robust to sensitivity checks, including weak instrument testing and consideration of omitted variables.</p>