Management and outcomes of children hospitalised with acute SARS-CoV-2 infection may differ throughout the pandemic or with admission type (clinical COVID-19, incidental COVID-19 or nosocomial infection).Describe the severity, management and outcomes of hospitalised children with acute SARS-CoV-2 infection in Australia across the first 4 years of the pandemic and compare between admission types, SARS-CoV-2 variants, age groups and immune status.A multi-centre prospective cohort study of 6009 children aged 0-16 years between January 2020 and June 2023.Most children (84.3 %) did not receive respiratory support, 33.4 % received antibiotics and 8 % were admitted to intensive care unit (ICU). Infants <6 months old were more likely to be admitted with clinical COVID than older children (12-16 years). Older children were more likely to receive antibiotics (27.8 % vs 43.9 %), corticosteroids (11.3 % vs 34.1%) or ICU admission (5.2 % vs 13.5 %). Compared to immunocompetent children, the immunosuppressed (7.7 %) were more likely to have nosocomial infection (9.5 % vs 3.9 %), receive antibiotics (57 % vs 25 %) or antivirals (18 % vs 4.4 %), but less likely to require respiratory support (93.4 % vs 83.8 %) or ICU admission (3.5 % vs 8 %). Children with nosocomial SARS-CoV-2 infection had higher rates of invasive ventilation (8 %) and ICU admission (21 %) compared to those with clinical (2.1 % and 7.1 % respectively) or incidental COVID-19 (4.8 % and 9.1 % respectively).Acute COVID-19 generally caused mild disease in hospitalised children, with management and outcomes differing by age and admission type. Similar outcomes were observed across the pandemic. Nosocomial SARS-CoV-2 infection was associated with more severe disease.