Amidst the prevailing vaccine misinformation today, there is an urgent need for new methods to verify, inform, and promote vaccination. One potential approach involves utilizing early childhood education institutions, such as preschools since every student must present an updated vaccination card for enrollment or re-enrollment. By instructing the school staff on how to verify vaccination records or conducting vaccination campaigns within schools, there is the possibility of improving vaccination rates. The study investigated vaccination coverage among children aged one to six years in public daycare centers in a municipality in the Vale do Paraíba region of São Paulo. A cross-sectional study was conducted, involving the collection of vaccination cards from two Municipal Early Childhood Education Schools (EMEI) in the area. The research considered children between the ages of one and six who were properly enrolled in the EMEIs during the data collection period, with exclusion criteria related to the illegibility of vaccination cards. Ethical clearance for data collection was obtained from the Research Ethics Committee involving human subjects, and informed consent was obtained from the children's guardians. Data were collected manually by analyzing copies of vaccination cards, and vaccination coverage was assessed based on the minimum 95% coverage recommended by the National Immunization Program (PNI) in Brazil. More than half of the analyzed vaccination cards (56.8%) were found to have outdated vaccination schedules. Several vaccines failed to achieve the recommended 95% vaccination coverage, including the measles, mumps, and rubella (MMR) vaccine, measles, mumps, rubella, and varicella (MMRV) vaccine, hepatitis A vaccine, varicella vaccine, and polio vaccine. In contrast, vaccines with adequate coverage included the Bacille Calmette-Guérin (BCG) vaccine, pentavalent vaccine, rotavirus vaccine, pneumococcal vaccine, meningococcal vaccine, and others. The analysis also revealed a concerning decline in childhood vaccination coverage, posing a risk not only in terms of resurgent diseases but also to the country's future economic productivity. As Brazil's population ages, failure to ensure children's access to vaccination may hinder their neurological, psychomotor, and social development, negatively impacting the future workforce. In conclusion, leveraging early childhood education institutions for vaccination verification and campaigns presents a promising strategy to improve vaccination rates in the face of increasing vaccine hesitancy and misinformation.