A connection substation (100) for a plurality of wave energy converters (WEC1, WEC2) being part of a wave power station (101), said connection substation comprising at least one transformer (102) and at least one connecting device (103) for electrically connecting a plurality of input power cables (C1, C2) to a common output cable (C3), wherein the connection substation (100) is provided with at least one buoyant body portion (104) for providing a buoyancy force and at least one fastening device (105) for securing at least one mooring line (106) connected to an anchor (107), wherein the at least one fastening device (105) is disposed in the vicinity of the bottom end (111) of the connection substation at a distance from an upper end (113) of the buoyant body portion (104), wherein the at least one connecting device (103) is disposed in a waterproof compartment in the connection substation (100), and wherein each of the plurality of input power cables (C1, C2) are run so that at least a portion of the cable ex
