While there is a rising focus on sleep issues among athletes, a notable gap exists in the comparative analysis of sleep patterns between male and female athletes. This study aims to evaluate the sleep patterns of collegiate swimmers during a specific period (pre-competition training phase) based on the National Sleep Foundation's recommendations and compares sleep differences between males and females. 15 swimmers (6 males and 9 females) completed the Athlete Sleep Screening Questionnaire (ASSQ) and wore actigraphy devices for 8 consecutive nights to record objective sleep patterns including bedtime, wake time, sleep onset latency, total sleep time, wake after sleep onset, and sleep efficiency. The total sleep time of collegiate male (5.0±0.4 h, 4.6 to 5.4h) and female (6.0±0.7 h, 5.5 to 6.5h) swimmers was less than 7 hours per night, and male swimmers' sleep efficiency (76.7±8.9%, 67.4 to 86.0%) was lower than the 85% standard. Male swimmers had less objectively measured sleep duration (p=0.006, d=1.66, large effect), lower sleep efficiency (p=0.013, d=1.51, large effect), and longer wake after sleep onset (p=0.096, d=0.94, moderate effect). Female swimmers had higher sleep difficulty scores (p=0.06, d=1.08, moderate effect), and there was a significant difference in the distribution of sleep difficulty scores between male and female swimmers (p=0.033, V=0.045, small effect). Collegiate swimmers exhibited poor sleep patterns during pre-competition preparation, and the sleep fragmentation of male swimmers was more pronounced. There were sex differences in both subjective and objective measured sleep patterns, with male swimmers having less sleep and low efficiency, while female swimmers experienced more significant sleep disturbances.