This chapter examines Southeast Asia’s significant underwater cultural heritage, which faces a range of threats. The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage has afforded greater protection to underwater cultural heritage worldwide but has been less effective in Southeast Asia due to its limited uptake. In light of this, the author uses case studies to argue for a broader understanding of how protection and preservation of Southeast Asia’s underwater cultural heritage can be achieved. These management approaches include cultural diplomacy, public-private partnerships, commercial involvement and the increasing professionalisation of maritime archaeology. While some of these approaches are in line with the principles enshrined in the 2001 UNESCO Convention, others are at odds with these principles. Despite this, we cannot afford to dismiss these alternative approaches, as the threats faced by underwater cultural heritage in Southeast Asia are time critical.