IntroductionActive school travel (AST) is an important contributor to child health, yet levels are low and declining in Aotearoa New Zealand. There is a paucity of research exploring change in AST over the earliest school years, a key life stage for setting AST habits for lifelong health gain. We aimed to measure transport mode shifts between 6 and 8 years of age, and identify factors associated with mode shifts. MethodsWe used data from the 6 and 8 year waves of the Growing Up in New Zealand Study, including 642 participants with AST measures at both times. Parents/caregivers were asked about their child's usual transport mode to/from school, perceptions about distance to school, school community cohesion, perceptions of their child at school, and a range of sociodemographic factors. At 8 years, children also self-reported perceptions of peer relationships and school. Factors associated with shifts from active to passive, and passive to active modes from 6 to 8 years were explored using stepwise logistic regression with backwards selection. ResultsAST was low at both time points (37% at 6 years, 34% at 8 years). Overall, 12% moved from active to passive modes and 9% moved from passive to active modes. Higher odds of shifting to active travel modes at 8 years were found for boys, living closer to school, parent-reported importance of living close to school, and child-reported peer relationships/liking school at 8 years. Only one factor was associated with changing to passive modes; for each one unit increase in school community cohesion at 6 years, the odds of changing to passive modes versus remaining with active modes was 15%. ConclusionFindings from this study highlight an urgent need for policy and practice to enable and encourage active travel modes for young children and their families.