The expanding needs for ocean resources, together with the design and diffusion of new kinds of deep-ocean and coastal management patterns, have changed profoundly in the transition from modern to post-modern society. As a result, the scientific approach to the ocean has also undergone profound changes, which have marked the epistemology of disciplines, their logical backgrounds and methods. This process has been driven by oceanography, which was born in the 19th century and has benefited, first, from the monitoring techniques from surface ships, then from the exploration of the water column and seabed, and finally from the satellite monitoring systems. While that process was evolving, geography has been involved in investigations of marine and coastal uses and the interaction between human communities and the ocean. Since the mid-1980s, and especially because of the inputs of Agenda 21 (United Nations Conference on Environment and Development, UNCED, 1992), oceanography has been required to deal also with deep-ocean and coastal management issues. To respond to this need, interaction of oceanography with other disciplines is essential. In this prospect geography has an important role because, on the basis of its heritage, it could contribute to (i) the epistemological discussion of the building up of ocean science, (ii) the analysis of the human communities/ocean ecosystems interaction, and (iii) the design of sustainable development-consistent management patterns. The conceptual background and external epistemology needed by ocean geography to optimise this role are presented and discussed.