Aims and objectives: To explore how the physical and social environment of acute mental health units influences consumers' perception and experience of safety. Background: Acute mental health units are places in which consumers should feel safe. Not all consumers, however, feel safe in this environment. Little is known about what contributes to consumers' feelings of safety in this setting. Design: The study used a qualitative descriptive design, influenced by naturalistic enquiry. Data were analysed using thematic analysis and are reported according to the COREQ checklist. Methods: Fifteen people who had experienced admission to an acute mental health unit were individually interviewed. Results: Having a supportive environment enhanced consumers' perception and experience of safety. A supportive environment was experienced when consumers had privacy, felt safe from other consumers and had meaningful activities to participate in within the acute mental health unit. In contrast, having their privacy breached by other consumers made participants feel unsafe. Many participants were fearful of other consumers, and felt unsafe and unable to protect themselves. Lack of meaningful activities led to boredom and contributed to consumers feeling unsafe. Conclusions: Personal spaces should address consumers' privacy needs without compromising staff access. Staff presence enhances consumers' feelings of safety, but this need can be heightened when consumers are unable to alert staff when they feel unsafe. Meaningful activities link consumers to their lives outside of the hospital and can enhance recovery. Relevance to clinical practice: Understanding how the acute unit environment is perceived by consumers can assist nurses and managers to promote feelings of safety among consumers. Feeling safe can, in turn, optimise recovery.