ESA will soon launch the Sentinel-3B Earth observation satellite to join its twin, Sentinel-3A, in orbit. The Sentineol-3 mission is part of Europe’s Copernicus environmental monitoring programme. The Sentinel missions are central to Copernicus, which offers a set of key information services for a wide range of practical applications. Data from the Sentinels are also free of charge and open to users worldwide. This video highlights a few examples of how Sentinel-3 is used for research into our oceans.