Objective Royal Canadian Mounted Police (RCMP) report extremely frequent and varied exposures to potentially psychologically traumatic events (PPTEs). While occupational exposures to PPTEs may be one explanation for the symptoms of mental disorders prevalent among serving RCMP, exposures occurring prior to service may also play a role. The objective of the current study was to provide estimates of lifetime PPTE exposures among RCMP cadets in training and assess for associations with mental disorders or sociodemographic variables. Methods RCMP cadets (n  =  772; 72.0% male) beginning the Cadet Training Program (CTP) completed a survey assessing self-reported PPTE exposures as measured by the Life Events Checklist for the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition-Extended. Binomial tests were conducted to compare the current results to previously collected data from the general population, a diverse sample of public safety personnel (PSP) and serving RCMP. Results Cadets reported statistically significantly fewer PPTE exposures for all PPTE types than serving RCMP (all p’s < 0.001) and PSP (all p’s < 0.001) but more PPTE exposures for all PPTE types than the general population (all p’s < 0.001). Cadets also endorsed fewer PPTE types (6.00  ±  4.47) than serving RCMP (11.64  ±  3.40; p < 0.001) and other PSP (11.08  ±  3.23) but more types than the general population (2.31  ±  2.33; p < 0.001). Participants who reported being exposed to any PPTE type reported the exposures occurred 1–5 times (29.1% of participants), 6–10 times (18.3%) or 10  +  times (43.1%) before starting the CTP. Several PPTE types were associated with positive screens for one or more mental disorders. There were associations between PPTE types and increased odds of screening positive for post-traumatic stress disorder (PTSD), major depressive disorder (MDD), generalized anxiety disorder (GAD) and social anxiety disorder (SAD) (all p’s < 0.05). Serious transport accident (11.1%), physical assault (9.5%) and sudden accidental death (8.4%) were the PPTEs most identified as the worst event, and all were associated with positive screens for one or more mental disorders. Conclusion The current results provide the first information describing PPTE histories of cadets, evidencing exposure frequencies and types much higher than the general population. PPTE exposures may have contributed to the cadet's vocational choices. The current results support the growing evidence that PPTEs can be associated with diverse mental disorders; however, the results also suggest cadets may be uncommonly resilient, based on how few screened positive for mental disorders, despite reporting higher frequencies of PPTE exposures prior to CTP than the general population.