This study empirically examines the effect of the expansion of public childcare centers on the enrollment rates of other types of childcare centers within the same region. Using nationwide childcare center data from 2019 to 2020, we apply a panel Difference-in-Differences (Panel-DID) approach. The results indicate that the expansion of public childcare centers significantly reduces the enrollment rates of other childcare centers. This finding suggests the presence of a potential substitution effect, whereby newly established public childcare centers partially crowd out demand for existing centers. Additional analyses reveal that the negative effect is relatively larger for private, home-based, and social welfare–run childcare centers, indicating that the policy effects are heterogeneous across childcare center types. Overall, the findings suggest that while the expansion of public childcare centers enhances access to childcare services, it may also reduce the number of children enrolled in existing childcare facilities. Therefore, future childcare policies should be designed with careful consideration of local demand conditions and existing childcare infrastructure. However, given the unique circumstances of the COVID-19 period and the non-random nature of public childcare center placement, caution is warranted in interpreting and generalizing the findings.