BACKGROUND: Snakebites pose a serious health risk to children in Sri Lanka, particularly in rural areas. Inappropriate first-aid measures and delayed hospital access contribute to adverse outcomes. This study examined caregiver first-aid practices and factors linked to harmful responses. METHODS: A descriptive cross-sectional mixed-methods study was conducted across four tertiary hospitals in Sri Lanka. Quantitative data were collected from 364 pediatric snakebite cases through structured caregiver interviews. First-aid practices were categorized as safe or potentially harmful. Logistic regression identified predictors of harmful practices. Additionally, 54 qualitative interviews explored caregiver beliefs and behaviours. RESULTS: While 264 (73.4%) caregivers washed the wound with soap and water and 222 (61.1%) reassured the child. Harmful practices were frequently observed: 97 (26.7%) applied tourniquets, 27 (7.4%) used herbal or home remedies such as lime or mashed onions, 9 (2.5%) attempted to suck out venom, 5 (1.5%) performed religious rituals before hospital care, 2 (0.5%) made incisions to drain blood, and 1 (0.2%) applied Condy's crystals. Harmful practices were significantly associated with low maternal education (AOR 1.94; p < 0.001), low paternal education (AOR 2.26; p < 0.001), low socioeconomic status (AOR 3.67; p < 0.001), and cultural beliefs regarding traditional cures (AOR 2.64; p < 0.001). Remote healthcare access was a borderline significant factor (AOR 1.28; p = 0.05). Prior training in snakebite first aid was protective (AOR 0.21; p < 0.001). Qualitative findings revealed coexistence of traditional and biomedical practices and frequent transport-related delays. CONCLUSION: Despite moderate awareness of recommended first aid, harmful practices persist in paediatric snakebite care in Sri Lanka. Targeted, culturally sensitive education and improved rural emergency transport services are essential to reduce delays and prevent complications.