AbstractResearch into opportunities for prevention including health promotion information about alcohol and other drugs (AoD) harms for people who go to prison is sparce. This is despite there being ample research reporting how much and how frequently AoD have been used by people who go to prison. This article describes results from a qualitative thematic analysis of interviews with 31 men in a Sydney prison, about where they first received health promotion information about AoD‐related harms and their first‐ever treatment episode. No participant reported receiving education on AoD harms or treatment support services in primary school or high school. Only one participant received their first treatment episode through a health service (in his case from a doctor) and none reported being screened for AoD use at a health service. Almost all (n = 27) participants had their first session with a trained AoD professional through the criminal justice system. Pro‐active screening in health services for AoD use disorders and referral to appropriate health services is needed.