Purpose: Bus drivers are at high risk of chronic diseases due to risk factors associated with poor diet, physical inactivity, high levels of sedentary behaviors, and unfavorable working environments. This study developed a mHealth program for bus drivers, and examined the effectiveness of a mHealth program for promoting physical activity among bus drivers using wearable devices and health coaching. Methods: Forty-seven workers from two bus companies were allocated to the experimental group and the control group. Participants were asked to wear a wearable device (Fitbit Charge HR) during waking hours for a day. Participants in the experimental group were provided with a Fitbit, weekly face-to-face health coaching, a mHealth workbook, and text and photo messaging for 12 weeks. The control group only received a Fitbit. Results: By week 12, there were significant differences between the experimental and control groups in exercise self-efficacy (p<.015) and daily walking steps (p<.001). Conclusion: The findings have demonstrated that the mHealth program using wearable devices and health coaching is effective for bus drivers for promoting physical activity. Based on our findings, it is recommended to encourage the mHealth program using wearable devices and health coaching for bus drivers' wellness.