Introduction The wide‐spread implementation of interventions to limit transmission and public health consequences of COVID‐19 in the Australian state of Victoria had flow‐on consequences for people who use and inject drugs. Consequences included the interruption of illicit drug supply and drug procurement, and the disruption to the delivery of health services. To inform strategies that can minimise the adverse outcomes of similar future disruptive events, this study explored how COVID‐19 restrictions impacted access to harm reduction and drug treatment services for people who inject drugs in Melbourne, Victoria. Methods Qualitative semi‐structured interviews were conducted via an online calling app, with 11 participants of a broader cohort study (the SuperMIX study) in April 2020. Interviews were focused on participants experiences of accessing and using harm reduction and drug treatment services. Data were thematically analysed using a process of blended coding. Results Findings revealed how disruptions in the delivery of harm reduction and drug treatment services—in response to COVID‐19 restrictions—created barriers accessing sterile injecting equipment, increased risk of arrest by police and exacerbated social isolation. Participants reported difficulties adapting to changes in services access, with some increases in injecting risk behaviours. However, improvements in opioid agonist therapy prescriptions were noted as a beneficial outcome. Discussion By examining the impacts of COVID‐19 and the resultant restrictions on people who inject drugs' access to health services in Melbourne, Victoria, findings provide guidance for future responses to the unanticipated large‐scale effects of the COVID‐19 pandemic, and similar disruptive events.