This pilot proof-of-concept study examined the feasibility and acceptability of a Continuing Care mobile application (app) designed to meet the recovery and personal support needs of individuals under justice supervision who were receiving outpatient substance use disorder (SUD) treatment. The study included adults on probation or parole who were enrolled in an outpatient SUD treatment program (N = 15; 86.7% males). Participants were instructed to utilize the Continuing Care app daily for 4 weeks. At the end of the study, they completed a satisfaction questionnaire. Of the 15 participants enrolled in the study, 12 (80%) completed the Continuing Care app modules and the satisfaction questionnaire, and all of these participants indicated high levels of satisfaction with the app (on a scale of 1-10, Mean = 1.8, SD = 1.2). The Continuing Care app was well-utilized and perceived as valuable by this group of low-income, underserved, and hard-to-reach individuals. Further research is needed to refine app content and evaluate its ability to meaningfully enhance and extend the benefits of SUD treatment.