Assessing Aquatic Literacy in Children: A Video-Based Study on the Reliability of Practical Assessment Criteria

Background Accidental drowning and insufficient physical activity remain major public health concerns among children worldwide. Aquatic Literacy provides a framework to support water safety, competence development, and lifelong participation in physical activity. However, evidence on the reliability of practical assessment approaches in educational contexts remains limited. Methods This study examined the inter-rater reliability of the practical components of the Aquatic Literacy for All Children (ALFAC) test battery. Twenty-one trained assessors evaluated standardized video recordings of 93 children performing nine isolated aquatic skills and one dynamic Parcours task. Reliability was assessed using Fleiss’ Kappa (κ) and Intraclass Correlation Coefficients (ICC), complemented by qualitative feedback from assessors. Results Substantial to almost perfect agreement was found for most isolated skills (ICC = 0.51–0.95). In contrast, reliability for Parcours tasks varied widely (κ = − 0.03 to 1.00), with lower agreement in tasks involving underwater movements, brief observation periods, and complex coordination. Qualitative findings highlighted unclear performance criteria and observational challenges as key sources of inconsistency. Conclusions The ALFAC test battery shows promising reliability for assessing discrete aquatic skills but requires refinement for complex tasks. Improving criteria clarity and assessor training may enhance consistency in educational settings. Reliable assessment of aquatic competence can support teaching practices, promote equitable learning opportunities, and contribute to water safety and participation in physical activity.