The Southern Ocean is the most remote and least known of the world’s major oceans. Wind, ice and fog loom large in its heroic narratives of maritime discovery and Antarctic exploration, but there has been little sustained attention to the natural and cultural histories of the marine environment and its place in Western and Indigenous histories. Drawing on the author’s recent history of the Southern Ocean, this paper examines the idea that writing ocean history is a form of environmental biography that moves between vastly different scales of time and space within one narrative. Telling the life story of an ocean demands that we cast our net into deep geological time, as well as examining recent understandings of the marine environment. It also compels us to move between global and local scales of storytelling, between themes of Western maritime exploration and scientific knowledge, for example, as well as local stories about specific places, cultures and species. This paper suggests that a biographical approach to writing ocean environmental history can offer a more evocative and nuanced historical perspective, as well as imparting a sense of history and agency to the ocean itself.