The Paris Agreement was largely understood as an implicit recognition of the need for a large-scale deployment of negative emissions technologies, in particular bioenergy with carbon capture and storage (BECCS), as part of an enhanced action on climate change mitigation. Yet, a large-scale deployment of BECCS, if feasible at all, would raise serious concerns relating to the social and environmental impacts of bioenergy, the safety of the transportation and the durability of the storage, as well as more general matters of cost-sharing, burden-sharing and responsibilities on the international plane. Although no international law instrument addresses these concerns specifically, some principles of general international law are relevant. Accordingly, this article identifies existing and emerging principles of general international law of relevance to BECCS and discusses the need for and opportunity of further developments.