Although universal jurisdiction over piracy has long existed in customary international law and international conventions, such as the Convention on the High Seas (HSC) and the United Nations Convention on the Law of the Sea (UNCLOS), the piracy situation has been changing. The subsidence of Somali piracy provides an opportunity for rethinking how to strengthen universal jurisdiction for maritime piracy trials to enhance a sustainable anti-piracy legal system. The incidents of Somali piracy have resulted in some new developments in exercising universal jurisdiction: the separation of seizing, prosecuting, and imprisoning States; the consideration of creative piracy prosecution mechanisms; the increased focus on land-based facilitation of piracy; enhanced international cooperation; and expanded universal jurisdiction. This leads to several main challenges in existing legal frameworks, including weaknesses in UNCLOS, the disharmony among international instruments, and defects in domestic piracy legislation. In order to sustain and improve the anti-piracy legal system, universal jurisdiction over piracy should be incrementally strengthened to support the prosecution of pirates by States. To address the trends and challenges, this article explores how the legal system can be enhanced in two respects: adjusting the basic provisions of universal jurisdiction over piracy and refining the relevant measures in exercising that jurisdiction to prosecute pirates.