An alarming number of injuries and drowning events occur at lifeguarded swimming pools. One strategy used in the aquatics industry to improve swimming safety is simulated drowning lifeguard audits. During audits, supervisors arrive unannounced and ask on-duty lifeguard(s) to rescue a dummy. This study tested whether audits effectively improve lifeguard surveillance and reduce swimmer risk-taking behaviors. A pre-post design examined lifeguard surveillance and swimmer risk-taking prior to, 3 days after, and a month after conducting unannounced lifeguard audits at 14 public swimming pools. Lifeguard surveillance and swimmer risk-taking were assessed via behavioral observation. Following the audits, lifeguards were less distracted and swimmers took fewer risks. Simulated drowning lifeguard audits appear to offer a useful strategy to improve lifeguard surveillance and decrease swimmer risk-taking at public swimming pools.