Preventive water competences that children should learn to be safe in the water have been discussed and revised. Methodology to promote these wáter competences has not had the same amount of examination and discussion so far. From an ecological perspective, we share some key points derived from the objectives of the research-into-action program called “The development of preventive water competences in 5th and 6th grade school students” as conducted in Junior Lifeguard programs in Uruguay. It involved six groups of 10 to 12-year-old Estate School students studied in two cycles. The whole process conveyed how our methodology changed from experiences and assessment results.