Traditional mindfulness-based interventions have been shown to reduce depression symptoms in pregnant women, although in-person classes may pose significant accessibility barriers, particularly during the COVID-19 pandemic. Mobile technology offers greater convenience, but little is known regarding the efficacy of self-paced, mobile-delivered (mHealth) mindfulness interventions in this population. This study tested the feasibility and acceptability of offering such an intervention for pregnant women with moderate-to-moderately-severe depression symptoms. We conducted a single-arm trial within Kaiser Permanente Northern California (KPNC). Participants were identified through KPNC’s universal perinatal depression screening program. Eligible participants included English-speaking pregnant women (<28 weeks of gestation) with moderate-to-moderately-severe depressive symptoms without a regular (<3 times/week) mindfulness/meditation practice. Participants were asked to follow a self-paced, 6-week mindfulness meditation program using a mobile app, Headspace™, 10-20 min/day. Outcome measures included feasibility, acceptability, and patient-reported outcomes (e.g., depression symptoms). Of the 27 women enrolled, 20 (74%) completed the study. Over half (55%) of participants used the app ≥50% of the days during the 6-week intervention. Responses to the semi-structured interviews indicated that women appreciated the convenience of the intervention and the ability to engage without having to attend classes or arrange childcare. We observed significant improvements in pre-postintervention scores for depression symptoms, perceived stress, sleep disturbance, and mindfulness. Our study demonstrates the feasibility and acceptability of an mHealth mindfulness intervention for women with moderate-to-moderately-severe antenatal depression symptoms. The preliminary data further suggest that an efficacy trial is warranted.