The Western and Central Pacific Ocean (WCPO) tuna fishery is the largest and most valuable in the world. Although the International Law of the Sea granted Pacific island countries the right to exploit and manage this valuable fishery, they have been unable to prevent resource decline or to capture economic development potential from their intersections with the global tuna industry. Variants of neoliberalism identify Pacific island countries' weak institutions to explain these failings. We argue that this explanation is insufficient. As an alternative, we offer a political economy analysis of the co-evolution of fisheries regulation and the strategies of the Japanese and Taiwanese fleets (and their governments) in the region. This framing illustrates the relational, multi-scalar processes within and among states and firms that shape patterns in the sector. Our findings indicate that the combination of competitive capital accumulation strategies and inter-state power relations must be addressed to explain challenges in the WCPO tuna sector.