Illegal, Unreported, and Unregulated (IUU) fishing is widely recognised as a transdisciplinary problem requiring holistic action at the international, regional and national level. The primary aim of the CAPFISH Project is to build capacity to address IUU fishing in developing states, by providing knowledge and tools to government actors on the front line of the fight against IUU fishing. Since the initiation of CAPFISH in 2021, the Project has offered four capacity-building workshops on IUU fishing. Much of the content of the first two workshops was captured in the first edition of this series. The second edition consolidates and expands on the content of Workshops 3 and 4, showcasing a range of articles on IUU fishing and related topics, including equity in fisheries, fishing-related crimes, transshipment, distant water fishing, fisheries subsidies, fisher fatalities and safety in the fishing industry, and the implementation of international instruments created to tackle IUU fishing and related matters. This edition also includes practitioner perspectives on IUU fishing from South Africa, Thailand, Peru, the Pacific Islands, Ghana, Senegal, Norway, the Philippines, Guyana, and the Republic of Korea.