Objective: The current study aimed to develop, implement, and evaluate the S.A.F.E.R. Near Water program, an evidence-based and theory-driven intervention targeting parent beliefs relevant to keeping children safe around water. Methods: A nonrandomized trial was conducted. Parents with children aged two through five years who were enrolled in lessons either at a public or private swim organization in Ontario, Canada were recruited and nonrandomly assigned to either an Intervention (N = 92) or Control (N = 150) condition. All parents completed the same questionnaire measures two times over the course of their child’s swim lesson session period, once at the beginning (preintervention) and again at the end (postintervention; approximately 9-15 weeks later). Questionnaires assessed parents’ perceptions related to supervision, child drowning risk, water safety, and optimism bias. Parents in the Intervention condition participated in S.A.F.E.R. Near Water, an educational water safety program comprising in-person seminars, informational handouts, and posters. Results: The S.A.F.E.R. Near Water program was associated with increased knowledge in targeted areas and effectively communicated most of the intended messages. A series of primary regression analyses revealed that parents receiving S.A.F.E.R. Near Water demonstrated improvements in: beliefs about the value of supervision; judgments about children’s swim skills and drowning risk; and perceptions related to swim lessons and children’s supervision needs (sr2 range: 0.22-0.38). Conclusion: These findings provide support for the feasibility and usefulness of a multifaceted, parent-focused, educational program delivered alongside children’s swim programming to promote closer adult supervision of children around water.