This retrospective cohort study aimed to examine the characteristics, incidence, temporal trends, and seasonality of paediatric injury-related Emergency Department (ED) presentations at a large metropolitan paediatric hospital. It included children aged ≤15 years who presented to the ED at The Children’s Hospital at Westmead, Sydney Australia, with a principal diagnosis of injury during the ten-year period from 1 January 2010 to 31 December 2019. Descriptive statistics were used to describe the characteristics of the cohort and the distribution of ED presentations by mode of arrival, triage category, discharge status, injury diagnosis. Negative binomial regression was used to examine percentage change in annual incidence. Seasonality was examined with Seasonal and Trend decomposition using Loess (STL). There were 134,484 (59.7% male children) paediatric injury-related ED presentations during the ten-year period, of which 23,224 (17.3%) were admitted to hospital. Head injury accounted for more than one-quarter (26.8%) of ED presentations. The average annual increase in incidence was more pronounced during the first five years (5.6% [95%CI 4.1% to 7.1%]) than in the last five years (0.8% [95%CI 0.2% to 1.5%]). The monthly incidence of ED presentations had a bimodal distribution with peaks during autumn (March–May) and spring (October–November) seasons. The mean number of ED presentations per day was higher on weekends (40.8 ± 0.3) than weekdays (35.3 ± 0.8). During 2010 to 2019, there was a significant increase in the annual incidence of injury-related ED presentations for children aged ≤15 years, with head injury accounting for more than one-quarter of the ED presentations. The incidence of paediatric injury-related ED presentations was higher during autumn and spring seasons and at weekends. These data will inform health resource planning and priority-setting and advocacy for child injury prevention strategies in Australia.