This article examines the role of European port authorities in assembling the green hydrogen frontier through the production of speculative connections with prospective hydrogen export zones in the global South. Specifically, it analyses the role of a particular discursive tool, the pre-feasibility report, in fixing the meaning of Namibian territory for the purposes of green hydrogen export, disembedding hydrogen products from the social, political and ecological bases of their production. We argue that the green hydrogen frontier is fundamentally a speculative project insofar as it both accentuates the productive indeterminacy of green hydrogen as an energy commodity and develops a series of discursive strategies designed to measure, map and capture the anticipated value of this commodity. The article’s findings advance geographical debates on energy, territory and speculation by demonstrating the role of the port authority - an under-researched actor in the literature on energy transitions - in the reimagination and transformation of littoral territories in the global South. Keywords: Green hydrogen, energy, territory, speculation, frontier, ports, the Netherlands, Namibia.