Objective: With most paediatric emergency research in Australia conducted at tertiary EDs, it is important to understand how presentations differ between those at tertiary paediatric EDs and all other EDs. Methods: Retrospective epidemiological study assessing paediatric case-mix and time-based performance metrics (aged 0–14 years) obtained from a national health service minimum dataset for the 2017–2018 financial year, comparing tertiary paediatric EDs and all other EDs. We defined a ‘major tertiary paediatric hospital’ as one which was accredited for training in both paediatric emergency medicine and paediatric intensive care. Results: Of the 1 695 854 paediatric ED presentations, 23.8% were seen in nine major metropolitan tertiary paediatric hospitals. Reasons for presentations were more distinctive between cohorts among children aged 10–14 years, where psychiatric illness (5.2% vs 2.5%) and neurological illness (4.5% vs 2.5%) were more commonly seen in major tertiary paediatric EDs. Australian Indigenous children were significantly less likely to present to tertiary paediatric EDs (3.0%), compared with other EDs (9.7%) (odds ratio 0.27, 95% confidence interval 0.26–0.27). While median waiting times were longer in major tertiary paediatric EDs (28 min [interquartile range 11–65]) than in other EDs (20 min [interquartile range 8–48], P < 0.001), patients were also less likely to leave without being seen (5.5% in tertiary paediatric EDs vs 6.9% in other EDs; odds ratio 0.80, 95% confidence interval 0.78–0.81). Conclusions: The present study identified key areas of difference in paediatric presentations between tertiary paediatric EDs and other EDs. It is vital to broaden paediatric ED research beyond tertiary paediatric centres, to ensure relevance and generalisability.