INTRODUCTION: The UNAIDS 90-90-90 targets for the cascade of care are widely used to monitor the success of HIV care programmes but there are few studies in children. We assessed the cascade for children and adolescents living with HIV in the national Collaborative HIV Paediatric Study (CHIPS) in the UK and Ireland. METHODS: Utilizing longitudinal data from CHIPS we compared the cascade of care for 2010, 2013 and 2016. Among children diagnosed with HIV and not known to be lost to follow-up at the start of each calendar year, we summarized the proportion in active paediatric care during that year (defined as having ≥1 clinic visit, CD4 or viral load measurement, or change to antiretroviral therapy (ART) regimen), and of these, the proportion on ART at last visit in that year. Among those on ART, the proportion with viral suppression (<200 copies/mL) and good immune status (WHO immunological stage none-/mild-for-age) at last visit in the year were summarized. Among those in care in 2016, outcomes were compared by current age, place of birth (born abroad vs. UK/Ireland) and sex. RESULTS: Of children in paediatric HIV care at the start of 2010, 2013 and 2016 (n = 1249, 1157, 905 respectively), the proportion in active care during that calendar year was high throughout at 97 to 99%. Of those in active care, the proportion on ART increased from 79% to 85% and 92% respectively (p < 0.001). Among those on ART, the proportion with viral suppression and good immune status was stable at 83% to 86% and 85% to 88%, respectively, across the years. Among children in care in 2016, those aged ≥15 years were less likely to be virally suppressed (79% vs. 91%, p < 0.001) or to have good immune status (78% vs. 94%, p < 0.001) compared to younger children; there were no differences by place of birth or sex. CONCLUSIONS: Children and adolescents in the UK and Ireland national cohort had high retention in care. The proportion on ART increased significantly over time although there was no change in viral suppression or good immune status. Poorer outcomes among adolescents highlight the need for targeted support for this population.