ObjectivesNon-communicable diseases are the leading cause of death worldwide, accounting for 71% of deaths in 2021. The chronic and pervasive nature of these diseases spurs the need for novel treatment approaches, including using the workplace as a front for the promotion and dissemination of health messages and activities. Taking this into consideration, this study aimed to assess the efficacy of a workplace health promotion program that targeted nutrition, physical activity, and obesity outcomes in a New South Wales (NSW) coal mine site.DesignA 12-week quasi-experimental pre-test–post-test study.SettingA coal mine site in rural NSW, Australia.ParticipantsAt baseline there were n = 389 participants, with similar numbers at follow-up (n = 420) as well as 61 participants from both timepoints (8.2% repeated measures), with 89% of participants being male.InterventionA multicomponent wellness intervention was implemented incorporating aspects of education, goal setting, and competition.OutcomesPhysical activity, nutrition, and weight.ResultsThe mean BMI at baseline was 30.01 kg/m2, and at follow-up 29.79 kg/m2(p = 0.39). At follow-up, participants reported 81% lower odds of engaging in the exercise category ‘no moderate physical exercise’ (OR = 0.09, p < 0.001), as well as 111% higher odds of meeting physical activity and exercise guidelines (OR = 2.11, p = 0.057). There were no changes to diet outcomes and no association between employment characteristics and participating in physical activity.ConclusionsWorkplace health promotion programs can be an efficacious strategy in improving physical activity outcomes and marginally improving weight outcomes in those in the mining industry. Further research is needed to determine the true effectiveness of these programs long-term, particularly in an environment as challenging and dynamic as the mining industry.