Introduction: In hyperendemic Aedes-borne settings, co-circulation of arboviruses creates diagnostic challenges in children with acute febrile illness. In Sri Lanka the last chikungunya outbreak occurred over 16 years ago, suggesting that most of the current paediatric population lacks prior immunity . In 2025, multiple districts reported chikungunya outbreaks, complicating differentiation from dengue due to overlapping early clinical features and the absence of a point-of-care diagnostic test. Objectives: To describe the epidemiology of chikungunya among children during the 2025 outbreak in Sri Lanka and highlight implications for clinical management in settings with cocirculating dengue. Methods: As chikungunya is not routinely notifiable, an online event-based surveillance system was established in late 2024 to detect clusters of chikungunya-like illness. Blood samples from clinically suspected patients were tested at the Medical Research Institute using RT-PCR and IgM/IgG ELISA. Concurrent dengue testing supported differential diagnosis. Nationwide trends and clinical observations were analyzed to inform practical diagnostic and management approaches. Results: Outbreaks were reported mainly from Jaffna (26%), Colombo (24%), Kandy (17%), Gampaha (9%), and Matara (7%). Children accounted for 15% of cases; among them 65% were male and 35% were female, with a reported peak age of 11–12 years. Infections were also reported among infants and neonates. A preliminary guideline was developed to support early diagnosis and management. Conclusions: The outbreak highlighted the need for laboratory-supported diagnostic pathways and updated paediatric guidance. Early differentiation of co-circulating arboviruses is essential to optimize outcomes and strengthen surveillance for timely public health response.