This paper interprets the disrupted establishment of the Kermadec Ocean Sanctuary, a 620,000 square kilometre marine protection area, as a crucial moment in Pacific frontier making. The development of large-scale protected marine areas is a politically charged frontier tool, in which states garner international recognition and environmental renown by setting aside large swathes of their exclusive economic zones. In the Kermadec Sanctuary, this enclosure hit against an assemblage of Indigenous histories, ecologies, repatriated fishing rights, and privatized fishing quota challenging the oftmarginalized agency of Indigenous people in frontier narratives. This paper argues that three factors are fundamental to untangling this conflict: first, the historical trajectory of terraqueous territorialization in the Kermadec region, second, the post-Treaty of Waitangi settlement dynamics of Maori marine environments, and third, the common ecosystem services model underlying conservation and extraction.