Introduction <p>Substance use disorders (SUDs) are a major epidemic in the USA. Patients who lack transportation may have limited access to outpatient SUD treatment programs and are less likely to remain in care. Encouraging the use of free, reliable transportation during enrollment is an untested mechanism for greater retention.</p> Methods <p>A pragmatic pilot study was conducted in Southwest Ohio between November 2020 and July 2022, among people with SUDs like opioid and alcohol use disorders who enrolled in an outpatient treatment program and screened positive for transportation barriers. Eligible patients were offered free, unlimited transportation for the first 12 weeks of treatment and randomized 1:1 to receive weekly text message reminders to schedule their ride (intervention) versus none (control). The primary outcome was retention in care at 12 weeks. Secondary outcomes included retention at 24 weeks and retention at weeks 12 and 24 when stratifying by those dispensed SUD medications (e.g., buprenorphine/naloxone, buprenorphine, methadone) at the treatment site versus not, and SUD type.</p> Results <p>The intervention arm included 171 patients and 190 patients were in the control arm. For retention in care at 12 weeks, there was not a statistically significant difference between intervention (77/171 = 45.0%) and control (81/190 = 42.6%) arms (odds ratio (OR) 1.10; 95% confidence interval (CI) 0.57 to 2.00, <i>p</i>=0.69). At 24 weeks, retention was lower for both the intervention (44/171 = 25.7%) and control (54/190 = 28.4%) arms but not statistically significantly different (<i>p</i>=0.54). Greater retention at 12 weeks was observed for the intervention versus the control arm among patients dispensed SUD medications but at week 24 there was no statistically significant difference. No differences were observed by SUD types at any time point.</p> Conclusion <p>Weekly reminders did not affect overall care retention but did at week 12 among patients dispensed SUD medications.</p>