In a relatively short span of time, ocean data have gone from sparse and patchy to a dynamic and continuous stream of information, at least for some dimensions of the marine environment. This relative progress in knowledge has developed in tandem with expanded anthropogenic pressure on the global ocean and its ecosystems. In this chapter, we trace the development of these two trajectories over the past three decades through discussions of two case studies, one focusing on the collection of ocean data and one on the application of digital data for marine management. Against the background of these two cases, we then discuss the relationship between increases in the availability of digital ocean data, possible uses of those data, and how they inform a rhetoric of ocean sustainability through promises associated with claims for expanding the blue economy. Our analysis aims to identify and elaborate on a disconnect between the digital transformation that is affecting all areas of environmental science and policy, including the ocean, and aims for and obstacles to achieving sustainable ocean environments.