Little is known about the knowledge and perceptions that inform children's safety in the aquatic environment. This paper reports on 8-9 year old children's critical thinking of water safety and safety strategies at the beach. One-to-one interview data with Year 4 students from across New Zealand, collected as part of the National Monitoring Study of Student Achievement, revealed insights that will contribute to water safety education. Data was obtained from video analysis of the interviews of children who chose the beach as the aquatic environment to talk about (N = 195). Most students (80%) could identify two things they do to keep themselves safe at the beach. In addition, almost half (48%) were able to identify two beach hazards and explain why each was dangerous. Some variation in understanding was evident when data was analysed by ethnicity and decile [New Zealand school deciles are a measure of the socio-economic position of a school's student community relative to other schools throughout the country. Deciles range from 1 (low) to 10 (high)] rating of the school attended. Unlike findings of other studies on high school and adult populations, no consistent gender differences were evident in children's perception of beach water safety. Implications for future beach water safety education in schools and the community at large are discussed and recommendations for curriculum change are made.