Vaccines against COVID-19 are likely to be approved for children under 12 years in the near future. Understanding vaccine hesitancy in parents is essential for reaching herd immunity. A cross-sectional survey of caregivers in 12 emergency departments (ED) was undertaken in the U.S., Canada, and Israel. We compared reported willingness to vaccinate children against COVID-19 with an initial survey and post-adult COVID-19 vaccine approval. Multivariable logistic regression models were performed for all children and for those <12 years. A total of 1728 and 1041 surveys were completed in phases 1 and 2, respectively. Fewer caregivers planned to vaccinate against COVID-19 in phase 2 (64.5% and 59.7%, respectively; p = 0.002). The most significant positive predictor of willingness to vaccinate against COVID-19 was if the child was vaccinated per recommended local schedules. Fewer caregivers plan to vaccinate their children against COVID-19, despite vaccine approval for adults, compared to what was reported at the peak of the pandemic. Older caregivers who fully vaccinated their children were more likely to adopt vaccinating children. This study can inform target strategy design to implement adherence to a vaccination campaign.