Globally, illegal, unregulated and unreported (IUU) fishing challenges economic development, as well as food and human security, and has done so for many years. Despite the implementation of legal responses to IUU fishing by the international community and many States, the problem continues. While political will, the vastness of oceans and limited human and financial resources hamper the effectiveness of these responses, fragmentation has also prevented effective control. IUU fishing is addressed by legal controls across fishing, shipping, labour and criminal law and existing research on IUU fishing has tended to focus on individual aspects of these, yet evidence indicates their interconnectedness. This research addresses a gap, critically analysing the range of international legal frameworks together. Within this context, this paper explores and analyses the how fragmentation of legal instruments, lack of interaction between actors and regimes, and piecemeal implementation of the law limits the control of IUU fishing drawing on the concept of regulatory pluralism to appropriately address the challenges.