This paper examines economic upgrading in the Canarium indicum (Canarium) nut industry in Vanuatu, the Solomon Islands and Papua New Guinea. Canarium is a tree that is indigenous to Melanesia, and has been the subject of several commercialisation attempts since 1988. The paper assesses the outcomes to various actors in the Canarium supply chain from attempts to upgrade industry products and processes by: (1) increasing the available resource in suitable locations; (2) improving nut products and processing techniques; (3) increasing actors’ knowledge and supply chain coordination; and (4) establishing product standards. A two-phase data generation process was implemented. Document analysis and participant observations of industry workshops initiated a set of four economic upgrading interventions that were adaptively implemented. A second stage of workshops and 76 interviews enabled outcomes to be assessed at the project’s end. Findings suggest that a small number of urban-based entrepreneurs benefit and subsequently are lead actors in industry development, but at the expense of benefits being distributed to a larger, more spatially disparate group of smallholder and small commercial growers. These economic upgrading outcomes are circumscribed by core-periphery relations in Pacific small island states and the scale of industry in each country. Thus, spatial inequalities are reproduced through the emerging Canarium industries. We argue that different routes to industry development are required in each country. Development initiatives that capitalise on the benefits of micro-enterprise clusters, joint action and regional institutional arrangements are proposed to overcome the impediments imposed by the particular geographies of Pacific island states.