My research investigates how Spanish scientists, environmentalists, and policymakers constitute ocean noise as an environmental threat in the Mediterranean Sea. Environmentalists use the term "ocean noise" to describe anthropogenic underwater sound produced by shipping, industrial, and military activity that is thought to be harmful to marine life. Concerns about the effects of ocean noise have precipitated scientific research and regulation across the Global North, including in the EU, which incorporated the regulation of ocean noise into its 2008 Marine Strategy Framework Directive. The Mediterranean Sea presents a particularly interesting case of ocean noise research, regulation, and environmental activism. My project asks how concepts, representations, and translations of sound move through science, civil society, and regulatory bodies. My research makes three contributions to current debates in the social sciences and humanities: First, it investigates the role of interspecies relations at macropolitical scales more often addressed in the literatures of environmental anthropology and political ecology. Second, I bring conceptual tools from science and technology studies and the anthropology of science to center the translation of interspecies relations within developing transnational regulatory regimes, a process less often traced in environmental anthropology and political ecology, and not yet in the Mediterranean region. In this sense, I also contribute to scholarly debates in the history and anthropology of the Mediterranean. Finally, by addressing sound as an object of governance, an object of scientific research, and an affective medium, my research contributes to interdisciplinary discussions across the humanities and social sciences about the interconnected structural, sensory, and embodied effects of the most pressing global environmental challenges of our time.