This study, conducted as part of an ICARS-supported project, assessed antibiotic use and the performance of antimicrobial stewardship (AMS) programmes across paediatric wards in five public hospitals in Zanzibar. Among 943 admitted children, 87.6% received antibiotics, with Watch-category antibiotics accounting for more than half of prescriptions. Although adherence to national treatment guidelines reached 77.8%, bacteriological testing was performed in only 10.9% of patients. AMS programmes scored below the threshold for basic functionality, with gaps in leadership, accountability, surveillance and feedback. The findings underscore the need to improve diagnostic practices, strengthen AMS programmes and support more appropriate antibiotic use in Zanzibar. Further research should assess prescribing practices and identify barriers to effective AMS implementation.