The paediatric flatfoot is a common presentation but it is unclear whether the condition will resolve on its own as the child gets older or whether treatment is required. Therefore, the study objective was to evaluate paediatric foot posture, and anthropometry, in children at two time points, three years apart.A sample of 1032 healthy children (505 boys, 527 girls; aged 5-11 years) was recruited for foot posture index (FPI) and anthropometry assessment (weight, height and body mass index, BMI). Assessment was repeated when the children were aged 8 years to 14 years. Paired t-tests, Anova, frequency tables and a multiple regressions were conducted.Initially, approximately 70% had a neutral FPI range, 20% pronated, 3% highly pronated, and 4% supinated. Initial mean FPI was 3.6 ± 2.8, being higher in boys 3.7 ± 2.8 than in girls 3.4 ± 2.7 (p = 0.034). All FPI categories changed over time, with supinated and neutral FPI increased by 19.5% and 4.7% respectively. In contrast, pronated and highly pronated FPI reduced by 10.6% and 55.6% respectively. Regression showed only 1% FPI change was explained by increased height. FPI scores were significantly reduced after three years (3.57 to 3.33; p < 0.001).Children's foot posture shifts toward neutral as age increases. There is minimal relationship with weight, height or BMI. Appreciation of developing foot posture could reduce over diagnosis and unnecessary treatment of paediatric flatfeet.