The study aimed to develop and validate a tool that assessed students' foundational movement skills, for primary school teachers. The playground circuit, including 14 movement skills (e.g. functional, locomotor and object control), was developed through insights and recommendations from teachers (n = 36) and academic experts (n = 25). To validate the Best Start Foundational Movement Skill Assessment Tool (BS-FMAT), a sample of children (n = 340; 159 boys and 181 girls; mean age = 6.1 ± 0.9 years) completed the circuit. Then, n = 120 randomly selected children completed the Test of Gross Motor Development (TGMD-3) and BS-FMSAT to determine concurrent validity. Multiple linear results showed significant and positive association between TGMD-3 and BS-FMSAT for overall skill ([beta] = 0.043, p < 0.001), locomotor ([beta] = 0.457, p < 0.001) and object control skills ([beta] = 0.334, p < 0.001). Findings provide preliminary evidence that BS-FMSAT is an alternative assessment tool for children in a New South Wales, Australia (NSW) primary school.