In contemporary public diplomacy, the idea of culture and nation-state are so intertwined that notions such as ‘national culture’ that fuel populism or culture as a soft-power resource often go unquestioned. This article critically revisits assumptions of state-centric diplomacy that tie culture to the state. Culture as a domain of the state, which helped carve up the world in the nineteenth and twentieth centuries, has become limiting in a twenty-first-century milieu that is both culturally diverse and interconnected. The article probes the communication dynamics that are untethering culture from the state and giving prominence to forces of increased separation as well as global collaboration, including the phenomenon of humanity-centred diplomacies. Humanity-centred diplomacies’ distinguishing features — global consciousness, holistic perspective, cultural diversity and process-orientation — suggest advantages over state-centric diplomacy for leveraging cultural diversity and tackling complex global problems.