The purpose of this document is to aggregate the coastal, flag and port State responsibilities to combat IUU fishing contained in select international fisheries instruments within a single reference document. The responsibilities are presented as a checklist, in questionnaire format. The document aims to serve both as a reference document for professionals as well as an assessment tool for practitioners, in order to facilitate the identification of legal, policy, institutional and operational weaknesses at the national level when implementing coastal, flag and port State responsibilities to combat IUU fishing. This is the first volume in the series of 'Checklists and technical guidelines to combat illegal, unreported and unregulated (IUU) fishing'