Understanding hospital service use among children with a diagnosis of craniosynostosis (CS) is important to improve services and outcomes. This study aimed to describe population-level trends, patterns, and factors influencing hospitalizations for craniosynostosis in Western Australia. Data on live births (1990–2010;n= 554,624) including craniosynostosis, episodes of death, demographic, and perinatal factors were identified from the midwives, birth defects, hospitalizations, and death datasets. Information on craniosynostosis and non-craniosynostosis-related admissions, cumulative length of hospital stay (cLoS), intensive care unit, and emergency department–related admissions were extracted from the hospitalization dataset and linked to other data sources. These associations were examined using negative binomial regression presented as annual percent change and associations of hospitalizations by age groups, demographic, and perinatal factors were expressed as incidence rate ratio (IRR). We found an increasing trend in incident hospitalizations but a marginal decline in cLoS for craniosynostosis over the observed study period. Perinatal conditions, feeding difficulties, nervous system anomalies, respiratory, and other infections contributed to majority of infant non-CS-related admissions.Respiratory infections accounted for about twice the number of admissions for individuals with CS (IRRs 1.94–2.34) across all observed age groups. Higher incidence of non-CS hospitalizations was observed among females, with associated anomalies, to families with highest socioeconomic disadvantage and living in remote areas of the state.Conclusion: Marginal reduction in the cLoS for CS-related admissions observed over the 21-year period are potentially indicative of improved peri-operative care. However, higher incidence of respiratory infection-related admissions for syndromic synostosis is concerning and requires investigation.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00431-023-04922-4.