Underwater cultural heritage (UCH) sites are unique in how their artifacts and archaeological contexts differ from terrestrial heritage sites, but UNESCO notes that UCH sites in less-actively regulated areas, like international waters, are at a high risk of having their material culture remains destroyed, pillaged, or commercially exploited, especially as technological innovations continue to increase access to the deep sea and its resources. International treaties like UNESCO's 2001 Convention on the Protection of the Underwater Cultural Heritage demonstrate efforts by the international community to protect UCH, however many maritime states including the U.S. have not signed it out of a concern that the treaty oversteps the international legal framework established by the 1982 UN Convention on the Law of the Sea (UNCLOS). In order to better understand how UCH is (or is not) protected in international waters around the world, this thesis examines the threats facing UCH in international waters as well as the contemporary legal frameworks designed to protect this cultural heritage. Several solutions aimed at addressing key threats facing UCH in international waters caused by these legal and regulatory systems and which can be taken by the U.S. and international community at large are also proposed. / Master of Arts / Underwater cultural heritage including shipwrecks, sunken port architecture, and even entire sunken cities provide important information about humanity's history of using the world's oceans and seas. Unfortunately, many of these underwater cultural heritage sites are highly at-risk of being accidentally destroyed or pillaged by people who are more interested in selling antiquities than learning about them. This problem is particularly exasperated in international waters, in which no country has the sole right to make or enforce laws to protect these cultural resources. While there are several international laws and treaties designed to protect underwater cultural heritage sites, some countries, including the U.S., have refused to sign them. To better understand why, this thesis discusses the risks facing underwater cultural heritage sites in international waters and the legal options available to help protect them. Several solutions aimed at addressing primary threats facing underwater cultural heritage sites and which the U.S. could adopt are also proposed.