Opioid overdose prevention training programs represent harm reduction initiatives for people who use drugs (PWUD). While studies have investigated their impact after participants have intervened in overdose situations, the impact of the training alone has not been examined in detail. This study explores the personal impact, including benefits and apprehensions, for PWUD who participated in a peer-led overdose prevention program and did not intervene post-training. Semi-structured interviews were conducted with 75 PWUD following training. Data collection took place in two phases (2016 and 2020; n = 37 and 38, respectively), and qualitative results of a thematic analysis are presented. The following participation benefits were reported, even if no naloxone administration occurred following training: improved sense of control and competency in potential overdose and other emergency situations, heightened feelings of responsibility to help others, overcoming social stigma, increased pride, confidence and self-esteem, renewed sense of hope, and changed drug use behaviours, namely reduced at-risk consumption behaviours. Over half of participants reported sharing prevention knowledge with others following training. As for apprehensions, participants reported: fear of intervening and of being stigmatized, disappointment and regret related to past overdose experiences, feeling burdened or stressed to intervene, and cutting ties with others to avoid overdose situations.