Background Evidence suggests that patients can meaningfully feed back to healthcare providers about the safety of their care. The PRASE (Patient Reporting and Action for a Safe Environment) intervention provides a way to systematically collect feedback from patients to support service improvement. The intervention is being implemented in acute care settings with patient feedback collected by hospital volunteers for the first time. Objective To undertake a formative evaluation which explores the feasibility and acceptability of the PRASE intervention delivered in collaboration with hospital volunteers from the perspectives of key stakeholders. Design A qualitative evaluation design was adopted across two acute NHS trusts in the UK between July 2014 and November 2015. We conducted five focus groups with hospital volunteers (n=15), voluntary services and patient experience staff (n=3) and semi‐structured interviews with ward staff (n=5). Data were interpreted using framework analysis. Results All stakeholders were positive about the PRASE intervention as a way to support service improvement, and the benefits of involving volunteers. Volunteers felt adequate training and support would be essential for retention. Staff concentrated on the infrastructure needed for implementation and raised concerns around sustainability. Findings were fed back to the implementation team to support revisions to the intervention moving into the subsequent summative evaluation phase. Conclusion Although there are concerns regarding sustainability in practice, the PRASE intervention delivered in collaboration with hospital volunteers is a promising approach to collect patient feedback for service improvement.