Little is known about people’s perceptions of how much swimming competency is required to provide protection from drowning, especially in open water environments where most drowning incidents occurs. This study reports on parental perceptions (n = 309) of swimming competency of themselves and their children, and parents beliefs on their safety when swimming in open water. Most parents (58%) considered themselves good/very good swimmers, although more than half (55%) considered that they could swim 25 m or less. Most parents (87%) reported that their children could swim, with more than one half (52%) believing that their child’s swimming competency was good/very good, yet most (74%) considered their child could swim only 25 m or less. Most parents (59%) and almost all children (81%) had never actually swum their reported distance in open water. In spite of these low levels of competency, one half (51%) of parents thought their children were safe/very safe in open water. The implications of an overly optimistic belief in the protective value of minimal levels of swimming competency for open water safety are discussed. Further exploration of the difference between real and perceived swimming competency, especially with at-risk groups such as males, are recommended.