Background/PurposeWe evaluated the minimally invasive surgery for congenital biliary dilatation (CBD) in adults and children and analyzed the surgical outcomes, especially in children aged <6 years.MethodsCharacteristics and surgical outcomes of patients with CBD who underwent minimally invasive surgery at our hospital between 2013 and 2023 were retrospectively reviewed.ResultsOverall, 129 patients (89 children aged <6 years, 9 children aged between 6 and 18 years, and 21 adults) were included in this study. Children exhibited more protein plug presence and abnormal biochemical data than adults. Incidence of postoperative pancreatic fistulas was highest in the adult group (3.4%, 11%, and 33%, respectively, p < .01). In children aged <6 years, postoperative bile leakage and pancreatic fistulas occurred in 9.0% and 3.4% of patients, respectively. Multivariate logistic regression analysis revealed that the Todani IVA was associated with a decrease in postoperative bile leakage (odds ratio: −1.7; 95% confidence interval: (−3.3)–(−0.22), p = .03).ConclusionAdults with CBD required prolonged operative times and had more short‐term complications than children with CBD. In children aged <6 years, minimally invasive surgery for CBD can be safely performed; however, a small diameter of the bile duct may be associated with bile leakage.