Policies requiring childcare settings to promote healthy eating, physical activity, and limited screentime have the potential to improve young children’s health. However, policies may have limited impact without effective implementation strategies to promote policy adoption. In this mixed-methods study, we evaluated the type, quality, and dose of implementation strategies for state-level childcare licensing regulations focused on healthy eating, physical activity, or screentime using: (1) a survey of state licensing staff and technical assistance providers (n = 89) in 32 states; (2) a structured review of each state’s childcare licensing and training websites for childcare providers; and (3) in-depth, semi-structured interviews with 31 childcare licensing administrators and technical assistance providers across 17 states. Implementation strategies for supporting childcare providers in adopting healthy eating, physical activity, and screentime regulations vary substantially by state, in quantity and structure. Childcare programs’ financial challenges, staff turnover, and lack of adequate facilities were identified as key barriers to adoption. Access to federal food programs was seen as critical to implementing nutrition regulations. Implementation resources such as training and informational materials were rarely available in multiple languages or targeted to providers serving low-income or racially/ethnically diverse families. There is a substantial need for implementation supports for ensuring policies are successfully and equitably implemented in childcare.