People who inject drugs face many challenges that contribute to poor health outcomes, including drug overdose, HIV, and hepatitis C infections. These conditions require high-quality prevention and treatment services. Syringe services programs are evidence-based harm reduction programs, and they have established track records with people who inject drugs, earning them deep trust within this population. In Baltimore, Maryland, although many syringe support services were limited during the COVID-19 pandemic, the health department's syringe services programs remained operational, allowing for the continuation of harm reduction services, including naloxone distribution. This evaluation describes a collaborative effort to colocate infectious disease testing and COVID-19 vaccination with a syringe services program. Our evaluation demonstrated that colocation of important services with trusted community partners can facilitate engagement and is essential for service uptake. Maintaining adequate and consistent funding for these services is central to program success. Colocation of other services within syringe services programs, such as medications for opioid use disorder, wound care, and infectious disease treatment, would further expand health care access for people who inject drugs.