At the national level, ineffective management, control and surveillance are the enabling factors of IUU fishing. Successful management of marine resources therefore relies on effective monitoring, control and surveillance strategies. Ideally these strategies are informed by scientific assessments of the nature and extent of IUU fishing within a nation’s waters. To date, no comprehensive studies have been conducted to identify and quantify IUU fishing within Palau’s EEZ. Our aim is to develop an interdisciplinary assessment of IUU fishing in Palau’s waters to support sustainable management of the PNMS, taking into consideration ecological, economic, social, political and institutional factors that need to be understood to effectively deal with IUU fisheries. Due to their high value on international markets and their generally prominent role in IUU fishing, efforts should be focused in particular on the catch of large oceanic predators, i.e. sharks, tuna and billfish.