Background and objectives: A caries epidemiological survey in daycare centers in the city of Hamburg, Germany, was conducted to determine the caries prevalence and the mean caries experience in 3- to 6-year-old children in 2016. The findings were compared with a survey conducted 10 years earlier. Special focus was placed on the caries burden of 3 year olds. Methods: A visual caries examination was conducted according to World Health Organization (WHO) criteria and with additional registration of initial lesions. A questionnaire was used to obtain information from the parents about tooth brushing in their children. Results: A total of 933 children were examined. The caries prevalence was 22.7%, the decayed/missing/filled teeth (DMFT) value was 0.8. Each child with caries had a mean of 3.5 affected teeth. Including initial lesions, the caries prevalence was 44.4% with a mean DMFT value of 1.8. Compared to the previous study, a further decrease in caries was observed. However, this was only minimal in the 3-year-old children. Of note is the already high incidence of initial caries in the 3 year olds. Univariate statistical analyses showed significant relationships between the start of tooth brushing (fewer caries when starting in the first year of life), daily tooth brushing frequency (more caries when brushing less than twice a day), and quality of oral hygiene (high caries burden with large amounts of plaque). Conclusions: The unfavorable results for the 3-year-old children and the correlations between tooth brushing and caries prove once again that structured caries prevention measures must begin well before the age of 3. This highlights the potential of the recently implemented dental screening examinations in very young children and the current recommendations for an early start of tooth brushing with fluoride-containing toothpaste for children.