Open water aquatic recreation is a significant cause of drowning, especially in developed countries that have easy access to aquatic environments. To simplify the plethora of safety messages promoted worldwide, 18 experts from 12 countries formed the International Task Force on Open Water Drowning Prevention (ITFDP) and published 16 generic, non-boating, open water safety messages. This paper examines the supporting evidence for the messages and makes recommendations for future research. A systematic review was undertaken of the literature published from 1990 to 2010. Task force members were also asked to provide the Secretariat with organizational recommendations or the evidence base that informed their decision-making. The review identified strong evidence bases for the importance of supervision and alcohol avoidance. Several messages were supported by some evidence such as lifeguards, CPR training, and life jacket use. The remaining messages had some supporting data and/or were organizational recommendations but lacked evidence demonstrating their efficacy. It identified where evidence to substantiate axiomatic wisdom is lacking and where research is needed to address gaps in our current knowledge of drowning prevention.