Purpose/Objective: Cardiac rehabilitation aims to reduce the likelihood of recurrent cardiac events through physical activity (PA) and education. There is limited understanding about the predictors of physical activity behavior in rural adults beyond rehabilitation. This study explored predictors of regular physical activity in rural adults, 6–12 months post cardiac rehabilitation. Research Method/Design: A self-report questionnaire (quantitative cross-sectional design) was mailed to a simple random sample of rural South Australians who previously participated in cardiac rehabilitation (n = 315). Regression modeling was adjusted for physical activity history and gender to examine psychological, social, and environmental predictors of (a) current leisure-time physical activity, self-reported through the Godin Leisure Time Exercise Questionnaire expressed as the Leisure Score Index (LSI) and the weekly frequency of physical activity bouts that cause sweating (“sweat frequency”), and (b) stage of physical activity behavior change according to the Transtheoretical Model of Behavior Change (“Stage of PA change”). Results: All measures of self-efficacy (barriers, task, and relapse), social assimilation, and self-regulation predicted LSI, whereas all measures of self-efficacy and self-regulation predicted both “Stage of PA change” and “sweat frequency.” Self-regulation explained the highest percentage of explained variance in LSI (31.6%) and “sweat frequency” (12.5%). Home social support additionally predicted “Stage of PA change”; there were no environmental predictors of any of the outcome measures. Conclusion: Similar to urban populations, the predictors of post–cardiac-rehab physical activity among rural adults predominantly emanate from the psychological domain. Findings support the need to strengthen the focus of cardiac rehabilitation program design on self-management skills and behaviors.