Consistent with international obligations, marine biodiversity protection in Australia is achieved primarily through the establishment of protected areas or sanctuaries, the sustainable management of fisheries and the protection of indigenous and endangered marine species. Australia historically has had a multiplicity of legislative regimes at a federal and state level that addressed the protection the marine environment. However, in recent years, with the adoption of Australia's Oceans Policy in 1998 and the passing of the Environment Protection and Biodiversity Conservation Act 1999 (C'th) (EPBC Act), the federal and state governments have begun to develop complementary management approaches for marine ecosystems and to put in place strong legal sanctions to enhance the protection of the marine environment. This essay provides an overview of the current legal and policy framework for the protection of marine biodiversity in Australia, with special reference to the enforcement of that protection through the EPBC Act. It reflects the state of the ongoing legal preceedings as at the time of writing. Using the recent decisions of the Federal Court in Humane Society International Inc. v. Kyodo Senpaku Kaisha Ltd. and Humane Society International v. Minister for Environment and Heritage as case studies, this chapter explores the effectiveness of the protection afforded by Australian laws in circumstances in which politics and complex international relations can undermine conservation objectives.