There has been significant research into the harms associated with injecting drugs and about the use of needle exchange programmes (NEPs) by adult injecting drug users (IDUs) in the United Kingdom. However, very limited research has been conducted investigating the knowledge, experiences and beliefs of IDUs under 18 years old, who due to their age are denied access to anonymous NEPs. This article reports on a small, exploratory study which examines the injecting practices of 16-19-year-old IDUs from Plymouth, UK. It investigates a range of injecting experiences, such as initiation into drug use, knowledge of harms and harm reduction strategies and the interviewees' perception of such practices. Results are presented from five in-depth semi-structured interviews. Analysis of the data indicated that peers play a significant part in injecting, particularly in terms of initiation and acquired knowledge. Also, it appears that knowledge does not necessarily lead to behaviour change, with some young people choosing to adopt high-risk practices despite knowing the potential consequences. This supports previous study findings in relation to young people's knowledge and associated behaviour, but also highlights the value placed on peers and their influence, particularly during the initial stages of an injecting "career".