Underwater cultural heritage (UCH) is a precious part of humanity’s shared history and heritage as it provides vital evidence and information about the interaction of humans with oceans, lakes and rivers. The Convention on the Protection of the Underwater Cultural Heritage was adopted by the General Conference of UNESCO (United Nations Educational, Scientific and Cultural Organization) in 2001 to protect this heritage which has become significantly vulnerable to threats such as pillaging, commercial exploitation and the development of the seabed with the evolution of marine technology in the latter half of the 20th century. The Convention celebrates its 20th anniversary in 2021 and has been ratified by 68 countries. Its annex, which provides rules about the activities directed at UCH, has become a major reference and is recognised as the established scientific standard for underwater archaeology and research today. Despite the growing recognition and application by the international community, the Convention has been ratified only by four countries in the Asia-Pacific region. Many underwater sites and shipwrecks have been commercially salvaged, particularly in Southeast Asia, and numerous artefacts recovered from the sites were often put up for auction, leading to irrevocable damage and loss of this valuable cultural heritage to future generations. This article as one of the themed articles dedicated to the UCH in Asia Pacific argues the roles of the Convention and the challenges and opportunities for the protection of UCH particularly in Southeast Asia. UCH contributes to the achievement of the Sustainable Development Goals and can play an important role in sustainable community and economic development. Its values and importance deserve to be widely recognised and advocated. Efforts for safeguarding cultural heritage in Asia Pacific needs to be pursued and enhanced through joining the 2001 Convention and with international support and cooperation.