Abstract Background There is a lack of information on changes in hospital admission rates for childhood-onset schizophrenia (COS), or on patient characteristics, to inform clinical research and health service provision. Aims To report age- and sex-specific incidence rates of hospital admissions and day patient care for schizophrenia (ICD-10 F20) and non-affective psychosis (ICD-10 F20-29), by year of occurrence and age, in childhood and adolescence. Methods Population-based study using person-linked data for England (available 2001–2016); time-periods in single years and 4-year groups. Results Hospitalised incidence for schizophrenia increased with increasing age, from 0.03 (95% confidence interval (CI) 0.02–0.05) and 0.01 (0–0.01) per 100,000 in, respectively, males and females aged 5–12 years, to 3.67 (3.44–3.91) in males and 1.58 (1.43–1.75) in females aged 13–17 years. There was no gender difference in hospitalised incidence rates in children aged 5–12, but in 13–17 years old, there was a male excess. Rates for schizophrenia were stable over time in 5–12 years old. In ages 13–17, rates for schizophrenia decreased between 2001–2004 and 2013–2016 in males, from 6.65 (6.04–7.31) down to 1.40 (1.13–1.73), and in females from 2.42 (2.05–2.83) to 1.18 (0.92–1.48). The hospitalisation rates for schizophrenia and non-affective psychosis, combined, in 13–17 years old decreased in males from 14.20 (13.30–15.14) in 2001–2004 to 10.77 (9.97–11.60) in 2013–2016, but increased in females from 7.49 (6.83–8.20) to 10.16 (9.38–11.00). Conclusions The study confirms that childhood-onset schizophrenia is extremely rare, with only 32 cases identified over a 15-year period in the whole of England. The incidence of schizophrenia and non-affective psychosis increased substantially in adolescence; however, the marked reduction in the proportion of those diagnosed with schizophrenia in this age group suggests a possible change in diagnostic practice.