INTRODUCTION: Most patients receiving opioid agonist treatment (OAT) smoke tobacco. Approved cessation interventions are less effective in this group than the wider population. We investigated how people on OAT experience nicotine vaping to quit smoking. METHODS: Patients on OAT randomised to the vaping arm of a smoking cessation trial were invited to participate in structured interviews incorporating broad pre-determined themes. A qualitative descriptive approach employing template analysis was used. Four authors coded transcripts, discussed discrepancies, modified the template using both inductive and deductive approaches. Authors made explicit their starting orientations and independent authors sought disconfirmatory data in a subsequent round of analysis. RESULTS: Four women and eight men (median age 44 years) participated, including four who identified as Aboriginal. Participants reported vaping as cheaper, more acceptable and less stigmatising than smoking but expressed concerns about ongoing accessibility due to the Australian prescription access model. Some found it technically challenging at first, but not more so than standard nicotine replacement therapies. Participants gave accounts of craving and withdrawal experiences, including supplementary use of nicotine patches, and compulsions to vape frequently and intensely, potentially indicating need for higher nicotine dosage. Participants generally reported that vaping helped them quit smoking, though some worried about swapping nicotine addictions. Others were glad to be using a lower-risk alternative. DISCUSSION AND CONCLUSIONS: This group reported varied experiences of nicotine vaping but were mainly optimistic that it could help them and others quit smoking. This was despite initial nicotine cravings and concerns about remaining addicted long-term.