The Widely scalable Mobile Underwater Sonar Technology (WiMUST) project is an H2020 Research and Inno- vation Action funded by the European Commission. The project aims at developing a system of cooperative Autonomous Under- water Vehicles (AUVs) for geotechnical surveying and geophysical exploration. The project will address underwater communication, acoustic distributed sensor array, mission planning and robot navigation, guidance and control issues. The paper gives an overview of the project objectives and methods.