It does so by measuring the extent to which RFMOs apply best practices against IUU fishing and pointing to the remaining gaps. Information gathered from RFMOs' resolutions and recommendations introducing conservation and management measures (CMMs), other publicly available sources and direct communication with RFMOs" secretariats was analysed and summarised into five indicators reflecting the most important management tools targeting IUU fishing at the disposal of RFMOs. Indicators show overall progress among RFMOs, but discrepancies remain, suggesting scope for improvement by learning from best performers.