The purpose of this paper aims to understand how ICCAT was modernized to be in line with contemporary international fisheries legal regime so as to adopt up-to-date CMMs and strengthen their enforcement through its convention amendment process, and its implications for Taiwan’s future participation under the capacity of a “fishing entity” in this organization. This paper found that the enforcement on the high seas fisheries governance in the Atlantic Ocean has been significantly strengthened after the modernization of ICCAT. Particularly, a HSBI scheme has been adopted in the Article XI (4) of the amended ICCAT Convention. In other words, ICCAT will as its own high seas boarding and inspection (HSBI) scheme similar to that of other Tuna RFMOs to ensure that the CMMs adopted by ICCAT will be effectively enforced. In addition, the target species it manages has been expanded from highly migratory species (tunas) to sharks and other relevant marine species, and many important conservation and management principles, such as precautionary approaches, ecological considerations, and best scientific evidence available have been incorporated in the amended Convention texts. However, in relation to Taiwan’s participation, although a fishing entity has been granted certain rights in the amended ICCAT Convention, but some are not, particularly the HSBI scheme. How Taiwan can overcome these disadvantages is therefore a major issue for its participation and negotiation strategies in the near future.