Sleep is considered an essential component of the pre and post-exercise recovery process. Research has indicated that training schedules have a significant effect on elite athletes’ behaviours such as the timing of food consumption and social schedules, yet few studies have documented the impact training schedules have upon elite athletes sleep/wake behaviours. The aim of this study was to examine the impact of training start times on the sleep/wake behaviour of Olympic swimmers prior to the 2012 Olympic Games. Methods Ten elite swimmers (8 male, 2 female) (mean age SD: 22.9 4.4 yr) participated in this study 16 weeks prior to the 2012 Olympic Games. Participants’ sleep/wake behaviours were monitored using wrist activity monitors and self-report sleep diaries for a 2 week period. Training schedules varied according to individual training programmes. Linear mixed models were conducted to examine the main effect of timing of training on sleep/wake behaviours. Results For training sessions before 06:00, athletes spent less time in bed (p < 0.01), obtained less sleep (p < 0.05) and woke up earlier (p < 0.001) compared to when training sessions were after 06:00. Bedtime and sleep efficiency did not differ significantly. Discussion Findings indicated that training start times influenced sleep/wake behaviours of athletes. Earlier training start times negatively affected athletes’ get-up times, and sleep duration. Given that cumulative sleep restriction may affect recovery and performance, these results suggest that repeated early-morning training may inhibit training and performance gains in elite athletes.