The long-term network comprising ocean bottom broadband seismometers (OBS) forms an integral part of the European AlpArray initiative and the German DFG Priority Programme SPP ‚Mountain Building in 4 Dimensions' MB 4D (http://www.spp-mountainbuilding.de/). The instruments are deployed with a mean distance of 25 nm (46km) to the neighboring station (28 nm (51 km) to neighboring three stations) west and north of the island of Corsica. The westernmost instruments are located near the Gulf of Lions and the northernmost instruments were installed off the Ligurian coast.The scientific aim of the LOBSTER project is manifold: (1) characterisation of the crust and upper mantle of the Ligurian Basin and the transition from the oceanic to the continental domain; (2) understanding the structures and kinematics of rifting during the opening of the Ligurian Sea; (3) imaging the prolongation of the Alpine front; and (4) studying the recent deformation in the Ligurian Basin and the surrounding coastal areas as imaged through local seismicity.Additionally, the AlpArray OBS network was important to complete the densely spaced AlpArray broadband seismic network. The technical aim of the LOBSTER project is to provide consistent data that can be smoothly integrated into the land data. Instruments have been deployed in June 2017 by RV Pourquois Pas and recovered after 8 months of recording in January 2018 by RV Maria S Merian (MSM71).