As field researchers have increasingly explored the methodological ‘backstage’ of their fieldwork, the relationship between researcher and assistant has come to the fore. While the literature has discussed gender, coloniality, and exploitation inherent to such work arrangements, less has been written about how the relation conditions and is conditioned by experiences of vulnerability. In this article, an assistant and a researcher address this gap analysing their relationship during a joint fieldwork experience in Colombia in 2021. We argue that the relation between researcher and research assistant should be conceived as being entangled in situations of vulnerability. We focus on vulnerability across and within the relation, highlighting the interactions of researchers and assistants’ positionalities and reflecting on how certain situations can heighten tensions of power and friendship. We show that a conceptualisation of the assistant–researcher relationship as conditioned by vulnerability allows us to consider the ethics arising from this relationship.