Tackling germs, negotiating norms, and securing access to medicines are persistent challenges that disproportionally affect developing countries’ participation in global health governance. Furthermore, over the last two decades, the excessive focus on global pandemics and security in global health diplomacy, rendered peripheral diseases that usually strike the poor and vulnerable, creating situations of marginalisation and inequality across societies. However, as the importance of regions and regionalism increases in global politics, and integration ambitions and initiatives extend beyond trade and investment to embrace welfare policy, there are new opportunities to explore whether and how regional commitments affect health equity and access to medicine in developing nations. What, if any, are the possibilities for meso-level institutions to provide leadership and direction in support of alternative practices of global (health) governance? Can regional polities become international advocacy actors in support of global justice goals? This article addresses these questions by analysing regional health diplomacy in South America. The paper argues that regional organisations can become sites for collective action and pivotal actors in the advocacy of rights (to health) enabling diplomatic and strategic options to member state and non-state actors, and playing a role as deal-broker in international organisations by engaging in new forms of regional health diplomacy.