Society is requesting more than ever being better informed on the state and effects of Earth’s changing oceans. This has direct implications on ocean observing systems, including scientific planning and technology. For instance better knowledge implies that data on health, climate and overall dynamics of our oceans have a known level of quality, be up-to-date, be easily discoverable, be easily searchable both in time and space, and be human- and machine-readable in order to generate faster decisions when and where needed. Requirements with respect to spatial regions and scales (seas and ocean basins, from millimeters to hundreds of kilometers), time scope and scales (past, present, future, from microseconds to decades) indeed have direct implications on observing systems’ spatio-temporal sampling capabilities. Possibly high spatial and temporal resolution also means unprecedented amounts of data, communication bandwidth and processing power needs. Technological implications are thus quite substantial and, in this short article, we will try to provide a review of some initiatives of global and local focus that are aiming to respond to at least some of these needs, starting with the application of the Global Earth Observation System of Systems (GEOSS) guidelines to ocean observatories. Then we will address real scenarios in real ocean observing facilities, first with the European Seas Observatory Network and the European Multidisciplinary Seafloor Observation (ESONET-EMSO), then two recently associated Spanish initiatives, the Oceanic Platform of the Canary Islands (PLOCAN) infrastructure and deep sea observatory in the Canary Islands, and the Expandable Seafloor Observatory (OBSEA) shallow water Western-Mediterranean observatory of the Technical University of Catalonia, one of the first real-time ocean observatories implemented with state-of- the-art interoperable concepts, down to the sensor interface.