The main objective of MODAS – Monitoring the Oceans with DAS – is the use of Distributed Acoustic Sensing on a submarine cable in the Azores to monitor for one year natural hazards (earthquakes and tsunamis) and the environment (sea state, surface currents, soundscape and whales). DAS is an emerging tool that uses the fibre as a sensor that measures strain and strain rate at a very high spatial resolution, typically 10 m or less. DAS is a very cost-effective tool to make long-term monitoring to several Essential Ocean Variables at distances from the coast up to 100 km. MODAS will investigate the solid earth, the ocean, solid ocean-interactions, anthropogenic and natural noise sources, whale vocalizations that will contribute to the mitigation of natural hazards and evaluation of the impacts of climate change on the Ocean. The DAS system was developed to attain a maximum sensitivity and a broadband response, from high-frequency whale vocalizations to long period tsunami waves and tides.