Aims: Workforce entry is a key transition period. It offers an ideal, but under-utilised opportunity to implement intervention strategies to prevent mental health and substance use problems among young people. A brief psychological wellbeing and substance use intervention targeting a high-risk group--apprentice chefs--was undertaken to explore this opportunity. Method: A RCT design (N ¼ 71) was used. The intervention group received two face-to-face sessions, and controls received five related information sheets during the first 2 weeks of training, with 4-month follow-up. Results: These apprentices were a high-risk group for alcohol and other drug harm and poor psychological wellbeing. At T1, 70% of the participants had AUDIT scores indicating problem drinking; 28% had used cannabis and 18% had used amphetamines in the last 12 months; and 24% had high K10 scores. At T2, the intervention group had significantly reduced risky alcohol use (p = 0.008), improved psychological distress (p = 0.045) and ability to talk with supervisors about work issues (p = 0.001) and cope with work stress (p = 0.001) and verbal abuse (p = 0.005), compared to the control group. Conclusions: Brief tailored interventions, delivered in an occupational training environment, have potential to reduce substance use risk and enhance young workers' psychological wellbeing.