Ocean renewable energy sources hold the potential to contribute to the options of low-carbon energy sources and enhance the efforts by the global community to slow down climate change. In this Chapter, we provide a brief background on the current state of technology and development of wave, tidal and ocean thermal energy and consider their potential as forms of renewable energy as well as the potential negative environmental footprints of ocean renewable energy installation and development. Secondly, we examine the relevant international legal and policy framework governing ocean energy, highlighting in particular, the absence of a global legal instrument that specifically regulates ocean renewable energy installations at the high seas. Thirdly, we identify current challenges to the roll-out of ocean renewable energy within the international regulatory framework. Lastly, we suggest policy and legal options available to countries to optimize the vast ocean energy resources.