North America's first supervised injection facility (SIF) was established in Vancouver, Canada, in 2003. Although evaluation research has documented reductions in risk behavior among SIF users, there has been limited examination of the influence of operational features on injection drug users' access to these facilities. We conducted an ethnographic study that included observational research within the SIF, 50 in-depth individual interviews with SIF users, and analysis of the regulatory frameworks governing the SIF. The government-granted exemption allowing the facility to operate legally imposes key operating regulations, as well as a cap on capacity, which results in significant wait times to enter the injecting room. Regulations that prohibit practices that are common in the local drug culture also negatively affect SIF utilization. Restructuring policies that shape the operation of the SIF could enhance access to the facility and permit SIF services to better accommodate local drug use practices.