introductionHepatitis C virus (HCV) is a global public health threat, and novel models of care are required to treat those currently or previously at highest risk of infection, particularly persons who inject drugs (PWID; ever injected), as conventional healthcare models do not have the reach to deliver cure of HCV to disadvantaged, disproportionately affected communities. In Western Europe and Australasia, it is estimated that HCV affects between 0.4% and 1.0% of the regions' populations, accordingly, it affects between 0.4% and 0.7% of the populations of countries in this study (Scotland, Wales and Australia). METHODS AND ANALYSIS: REACH HCV is an international multicentre cluster randomised controlled trial with sites in Scotland, Wales and Australia. The sites are community pharmacies which are randomised equally to one of two pathways: the pharmacy intervention pathway or the education-only (control) pathway. Participants are recruited from OST clients in these pharmacies.In the pharmacy intervention pathway, participants receive a rapid point-of-care HCV PCR test in their pharmacy by a study outreach nurse. If positive, direct-acting antivirals (DAAs) are delivered to participants via their pharmacist in line with their OST schedule.In the education-only pathway, pharmacists counsel OST clients on HCV and refer them to the nearest nurse-led clinic or general practitioner offering HCV testing according to standard care protocols. If positive, DAAs are delivered as in the intervention pathway.The primary endpoint for both pathways is sustained viral response at 12 weeks post-treatment . Secondary outcomes are: cost-efficacy by pathway; participants tested by pathway; adherence to therapy by pathway and impact of blood test results on treatment decisions.A statistical analysis plan will be finalised prior to data lock. Analysis will be by intention to treat (ITT) to show superiority. Modified ITT analysis will also be undertaken to explore the steps in the pathways. ETHICS AND DISSEMINATION: The trial received ethical favourable opinion from the East of Scotland Research Ethics Committee 2 (19/ES/0025) for UK sites and approval from the Alfred Hospital Ethics Committee (148/19) for Australian sites and complies with principles of Good Clinical Practice. Final results will be presented in peer-reviewed journals and at relevant conferences. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry NCT03935906. PROTOCOL VERSION: V.4.0-19 March 2020.