We explored participants’ experiences of a counsellor-supported PTSD Coach mobile application intervention (PTSD Coach-CS) in a randomised controlled trial. PTSD Coach-CS participants, who received the intervention and self-completed a custom-designed questionnaire at intervention completion were included (n = 25; female = 20; ages 19–59; isiXhosa = 22). This questionnaire comprised questions regarding the feasibility, acceptability and potential impact of the PTSD Coach-CS intervention, and general psychological support in our setting. Data were analysed using Braun and Clarke’s thematic analysis. Three main themes emerged. (i) Participants’ largely positive experiences of treatment procedures included the safe space created by the counsellor support in combination with the PTSD Coach application, allowing them to learn about and understand their lived experiences, and to accept their PTSD diagnoses. (ii) Positive perceptions of the PTSD Coach application, yet raising important concerns (e.g., lack of family involvement) for future consideration. (iii) Intervention-specific and systemic treatment barriers (e.g., stigma) providing important information to inform and increase the usefulness of the PTSD Coach-CS intervention. The findings suggest that the PTSD Coach-CS intervention may help address the need for access to suitable care for South African adults with PTSD. Some contextual barriers must be considered in further intervention implementation.