This paper offers a conceptual contribution to understanding ocean governance and the management of spaces for the protection of marine biodiversity, organization of extractive industries, the arrangement of global shipping and other ‘blue-economy’ uses. Rather than focus on one type of management technique (such as a Marine Protected Area (MPA) or example of Marine Spatial Planning), or a site- or species-specific case study of governance, this paper offers a theoretical tracking of the uncharted territories of governance that foreground ocean management approaches. The literature on ocean governance and management techniques predominantly derive from scientific disciplines (which provide the basis for planning) and policy-related social science fields, leaving a lacuna in more critical discussions of ways of knowing and understanding the world that drive it. The paper argues the need to critically understand the ontologies (the regimes of what we believe exists) and geophilosophies (the geographically informed modes of thinking) of territory that underscore ocean management to make sense of its past successes and failures, its present functioning and its future directions. This paper argues that without critical consideration of the kinds of thinking—the ontologies and geophilosophies—that drive ocean management, it will lack the transformative potential many hope it will achieve for sustainable development. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.