Vulnerable and socially excluded groups in society persistently experience worse oral health and poorer access to dental services than the mainstream population. This article reports on the qualitative component of a feasibility trial evaluating a link work intervention to support individuals with severe mental illness to access dental healthcare in Northwest England. Using the Candidacy Model as a conceptual framework, interviews with eighteen participants and the three link workers were carried out to explore the challenges individuals face in navigating access to dental services and how this is negotiated with health professionals and systems. The findings show how the consequences and significance of poor mental health impede access to dental care that is already scarce and hard to reach. The link workers mediated candidacy by taking on some of the burdens of access and providing a buffer to power differentials built into the healthcare system. They provided person-centred support that participants valued as holistic and non-judgemental. As a result, participants felt more able and willing to return to dental services in the future. The discussion considers how the literature on candidacy can be helpful in understanding how link work interventions may reduce inequalities in access for vulnerable groups but are dependent on wider organisational conditions and provision.