Background <p>On January 31^st 2023, the Canadian province of British Columbia temporarily decriminalized the personal possession of certain illegal drugs up to 2.5&#xa0;g, cumulatively, for adults. A stated aim of this policy directive was to reduce the stigmatization of people who use drugs and increase access to health and harm reduction services. The aim of this study was to capture the prevalence and nature of potential barriers to such services under drug decriminalization.</p> Methods <p>We employed a mixed-methods study design, triangulating survey data from harm reduction service users in 2022 (<i>n</i> = 503) and 2023 (<i>n</i> = 433) alongside qualitative interviews with people who use drugs in British Columbia (<i>n</i> = 78) collected in 2023. Qualitative and quantitative findings were analysed convergently.</p> Results <p>Findings across both datasets suggest that reported barriers to health and harm reduction services persisted during British Columbia’s decriminalization pilot. Quantitative and qualitative data reflecting these barriers are presented in parallel under four themes: (1) stigma and fear of substance use disclosure, (2) stigma and access to services, (3) service-specific barriers, and (4) police-related barriers.</p> Conclusion <p>Decriminalization alone may be insufficient to address and/or mitigate the barriers that continue to constrain people who use drugs’ access to care. If the policy goal is to reduce barriers to health and harm reduction services, additional structural and institutional supports may be required.</p>