Introduction – Inadequate vaccination coverage poses an epidemic risk for vaccine-preventable diseases. To obtain indicators of vaccination coverage among 3- to 4-year-olds at the sub-departmental level, data from health checkups of 3- to 4-year-olds enrolled in school in the Alpes-Maritimes department were analyzed. The primary objective of this study was to assess the feasibility of using these data and their representativeness. The secondary objective is to evaluate changes in vaccination coverage following the new vaccination requirements for children born in 2018 and later. Methods – Data on cohorts of children born in 2017, 2018, and 2019 were provided by the Departmental Council. Representativeness (proportion of school-aged children who underwent a health checkup) and the completeness rate of vaccination status (proportion of children with a completed vaccination record among those who underwent a health checkup) were calculated. The overall vaccination coverage rate among 3- to 4-year-olds was broken down at the departmental and municipal levels for each cohort. Results – The representativeness of health checkups ranged from 79% for the 2017 (9,584/12,173) and 2019 (9,299/11,776) to 96% (11,429/11,913) for the 2018 cohort. The completeness of vaccination status ranged from 96% in 2017 to 95% in 2018 and 2019. The median vaccination coverage rate at the municipal level ranged from 74.3% (interquartile range, IQR=16.9%) for the 2017 cohort to 88.3% (IQR=13.8%) for the 2019 cohort. Conclusion – Data from health checkups allow for robust estimates of vaccination coverage at the sub-departmental level. An increase in, as well as greater homogeneity of, vaccination coverage was observed between the 2017 and 2019 cohorts, following the expansion of mandatory vaccination in 2018. This method could help identify under-vaccinated municipalities in order to implement targeted catch-up vaccination measures.