Background and aimsPhysical activity interventions have been shown to prevent postpartum depression. However, few studies have targeted low income women who are at high risk for postpartum depression. MethodsThis study examined the efficacy of a novel remote physical activity intervention designed to prevent perinatal depression (assessed at 36 weeks gestation and 12 week postpartum). Participants (n = 111) who were low income and pregnant (less than 20 weeks) were randomly assigned to either a six month intervention focusing on increasing physical activity and decreasing sedentary behavior (remote counseling sessions based on Self-Determination Theory) or usual care. All participants wore a Fitbit throughout the study to monitor their activity levels. The Edinburgh Postnatal Depression Scale and Perceived Stress Scale were administered at baseline, 36 weeks gestation, and 12 weeks postpartum. ResultsThere was no effect of the intervention on depressive symptoms or perceived stress at either of the timepoints. Secondary analysis indicated that lower levels of sedentary behavior, β = 0.256, p < 0.05, and higher levels of light activity at 8–12 weeks postpartum was related to lower perceived stress at 12 weeks postpartum, β = −0.284, p < 0.05. ConclusionEven though there was no effect of the intervention on preventing depression and stress, it continues to be important for clinicians to discuss the importance of activity during the perinatal phase due to the many health benefits. There is some evidence that sedentary and physical activity behavior may be important for reducing stress levels, however, additional research is needed.