Oceans, integral to a healthy global ecosystem, are protected partly through marine protected areas (MPAs). Despite numerous MPAs within national jurisdictions, the Areas Beyond National Jurisdiction (ABNJ) remain significantly neglected. Currently, most MPAs in ABNJ are governed by the OSPAR or CAMLR frameworks, which exhibit substantial deficiencies due to the fragmented state of international laws. United Nations Convention on the Law of the Sea (UNCLOS), for instance, offers limited provisions for ABNJ. To address these legislative gaps, negotiations for the Biodiversity Beyond National Jurisdiction (BBNJ) were initiated, leading to the successful adoption of the BBNJ Agreement in March 2023. This paper critically examines the existing regional treaties overseeing high-seas MPAs and explores the innovative approaches introduced by the BBNJ Agreement for the conservation and sustainable use of marine biological diversity in ABNJ. The analysis concludes that the BBNJ Agreement provides a more comprehensive and sustainable management framework for high-seas MPAs, thus effectively overcoming the limitations inherent in regional treaties.