Substance use disorder is an international problem. Rates of substance use disorder in South Africa are increasing, particularly among the youth, and relapse rates are high. A range of treatment modalities and support programmes are used to treat substance use disorder. Possible selves is a theory of self-concept and behaviour motivation suggesting that self-concept has future components, namely, hoped-for selves, feared selves and expected selves. These serve to motivate behaviour either towards or away from an aspect of self and may be useful in personalising rehabilitation and contributing to maintained sobriety. In this qualitative study, we used a phenomenological design to sample nine participants in a treatment centre in Gauteng, South Africa. These participants engaged in the possible-me-tree-drawing activity to explore their hoped-for, feared and expected possible selves. The findings of hoped-for selves as sober, educated and in healthy relationships were identified. Feared selves included self as a life-long addict, homeless and alone. The participants discussed expected selves as family members and independent. The participants felt that the activity was useful to them. All participants stated that identifying their possible selves would help them to maintain sobriety after leaving the treatment facility. Based on these findings we recommend that possible selves be implemented in treatment programmes for substance use disorder. We also recommend that future research include replicating the study, including a longitudinal component and comparison studies based on a quasi-experimental design.