This paper reports the Australian findings in an international study comparing self-reported and actual swimming and aquatic skills of young adults. Physical Education and Sports Sciences students (n=263) completed the “Can You Swim?” self-report survey and practical skills assessment, unaware that the practical tests replicated survey items. Relationships for comparisons between practical tests and their matched survey item were weak, indicating participants had inaccurate perceptions of their own swimming skills. Typically, they underestimated their competence in terms of distance and fundamental aquatic skills. Understanding of what constitutes different levels of swimming ability was poor, for example, most participants identified as average or good to excellent swimmers, but more than half of self-identified average swimmers, and 20% of good to excellent swimmers, estimated they could complete <100m of continuous swimming. The implications of study findings for drowning prevention and the need for further research are discussed.