BackgroundAmidst the ongoing drug poisoning crisis across North America, drug checking services (DCS) are increasingly being implemented as an intervention intended to reduce drug-related harms. This study sought to identify key opportunities and challenges influencing the implementation of DCS in British Columbia (BC), Canada. MethodsBetween January 2020 and July 2021, semi-structured, in-depth interviews were conducted with 21 individuals involved in the implementation of DCS across BC (i.e., policymakers, health authority personnel, community organization representatives and service providers). The Consolidated Framework for Implementation Research (CFIR) was used to guide coding and analysis of the interviews. ResultsBy bringing in a wealth of knowledge about community needs and concerns, in addition to a passion and energy for social justice and health equity, community members and organizations with a dedication for harm reduction played a critical role in the successful implementation of DCS in BC. Other significant facilitators to implementation included the preventive benefits of DCS that made the intervention compelling to policy influencers and decision makers, the provincial public health emergency regarding overdose that shifted the regulatory environment of DCS, the adaptability of DCS to meet concerns and needs in various contexts, including via ongoing processes of reflection and evaluation. Barriers to implementation included criminalization and stigmatization of drug use and people who use drugs and lack of funding for community-led implementation actions. ConclusionsAlongside structural reforms that address the underlying contextual factors that influence implementation (e.g., decriminalization of drugs, increased funding for DCS), centering community expertise throughout implementation is critical to the success of DCS. Our findings provide important insights into how BC can successfully implement systems-level harm reduction interventions and offer insights for other jurisdictions in their implementation of DCS.