This article calls for the norm of free, prior, and informed consent (FPIC) for indigenous peoples to be applied to deep sea mining (DSM) projects carried out in the international seabed, particularly in the Pacific region, where numerous indigenous communities stand to be directly and disproportionately impacted by this new extractive industry. Our argument, while novel, relies on core prescriptions of Part XI of the United Nations Convention on the Law of the Sea (UNCLOS) requiring compliance with international law in general, including pertinent rules of international environmental and indigenous rights law. UNCLOS’s clear parameters on the prevention of harm to the marine environment, expounded upon by the International Tribunal for the Law of the Sea in a series of key decisions, have created a due diligence standard that is imposing ever higher duties on an increasingly wide range of actors, including in areas beyond national jurisdiction. This standard is evolving alongside a robust norm requiring the FPIC of indigenous peoples threatened by large-scale extractive activities, even if those activities are not directly carried out on indigenous land. When applied to DSM, whose exploratory stage has already resulted in an array of adverse impacts to Pacific indigenous peoples, these normative legal developments coalesce into a compelling argument for placing impacted indigenous peoples into key decision-making roles. Such an approach, which we call a “second wave” of due diligence, represents a decisive break from a destructive history in which the Pacific served as a proving ground for the experiments of others, and a concrete step toward sustainable, rights-based development in the twenty-first century and beyond.