ABSTRACT In studies of migrant healthcare, ‘brokerage’ is conceptualised as the process by which community health workers facilitate low-income migrants’ access to the formal healthcare system, acting as both gatekeepers to healthcare and representatives advocating for patients. Building on these conceptualizations, we examine brokerage within what we call the ‘Third Net’ of the U.S. healthcare system, an informal health network comprised of mostly volunteer-run, community-based organisations and clinics that provide medical care to uninsured, undocumented migrants. Our study draws from 52 in-depth interviews with volunteers and a cumulative 23 months of ethnographic fieldwork with two migrant-serving organisations in Houston, Texas, and Phoenix, Arizona. We argue that brokerage roles and relationships within the Third Net are necessarily marked by versatility. This versatile brokerage in the Third Net (1) facilitates ad hoc access to the mainstream health system for uninsured, undocumented migrants; (2) challenges migrants’ racialized disentitlement and discourses of migrant dependency; and (3) de-centers and expands broker roles. Contributing to migrant health and brokerage literature, this research illustrates that brokerage relationships are not always fixed and hierarchical; brokering care is not solely about access to an inequitable health system but can also involve creating new and more equitable configurations of care.