Assessments of regional cooperation in the Pacific islands have often identified cooperation in oceanic fisheries, namely tuna, as a shining example of successful Pacific islands cooperation. This chapter identifies the various factors that have facilitated successful cooperation in this area. Tuna has long been recognized as one of the most commercially valuable resources in the Pacific islands region. The waters of the Pacific, covering an area of around 50 million square kilometers or over ten per cent of the Earth’s surface, are among the most productive tuna fishing grounds in the world. These provide around one third of the world’s tuna supply to global consumers and are an important (in some cases crucial) component of the food security and development prospects of the Pacific island communities.