Background: Royal Canadian Mounted Police (RCMP) report diverse occupational stressors and repeated exposures to potentially psychologically traumatic events, which may increase the odds of screening positive for a mental disorder, and increase the risk of death by suicide. The current study was designed to provide prevalence information regarding suicidal behaviours (i.e., ideation, planning, attempts) and assess for sociodemographic differences among cadets at the start of the RCMP Cadet Training Program (CTP). Method: Cadets (n = 736, 74.0% male) were administered the structured Mini International Neuropsychiatric Interview by a mental health clinician or a supervised clinical psychologist trainee. The interview includes an assessment of past month suicidal ideation, planning, attempts and lifetime suicide attempts. Results: Within 1 month of starting the CTP, a small percentage of cadets reported past month suicidal ideation (1.6%) and no cadets reported any suicidal planning (0%) or attempts (0%). Lifetime suicide attempts were reported by (1.5%) of cadets. Conclusions: The current results provide the first information describing the prevalence of suicidal ideation, planning, and attempts among RCMP cadets starting the CTP. The estimates of suicidal behaviours appear lower than the general population and lower than reports from serving RCMP. Higher prevalence estimates of suicidal behaviours reported by serving RCMP, relative to lower estimates among cadets starting the CTP in the current study, may be related to age, cumulative experiences or protracted exposures to operational and organizational stressors, rather than insufficient screening of recruits.