The COVID-19 pandemic and resulting mitigation measures have led to increased vulnerabilities in early child development. However, research is scarce and there are no studies on the persistence of these losses three years into the pandemic among young children. To fill in this gap, we examined census-like evaluations of school readiness carried out among preschoolers in Uruguay. The assessments were carried out among 5 cohorts of 5-year-olds: who were assessed prior to the pandemic (2018, 2019); during the pandemic (2020, 2021); and after the health emergency declaration ended in Uruguay (2022). A total of 180,984 teacher evaluations were included covering cognitive, motor and socio-emotional development, as well as attitudes toward learning. Overall, we found that scores in most spheres of child development decreased from before to during the pandemic in 2020 and 2021. In 2022, scores returned to pre-pandemic levels. Our findings suggest the recovery of developmental losses among cohorts of children in kindergarten took more than two years in a country that experienced a mild-to-moderate impact of the COVID-19 pandemic.