The aim of the present invention is to propose an offshore aquaculture installation in a healthy environment for fish, having the smallest possible impact on the environment in terms of pollution, with a combination of technical means ensuring the stability of the structure and the safety of humans, with all the equipment necessary for easy offshore operation. This aim achieved by an offshore aquaculture installation comprising one or a plurality of cages (1) for breeding fish and a floating structure (2) that is ballasted and submersible. The installation is characterised in that it comprises a main anchoring device having an anchor line (3) linked on one side (6) of the structure (2) and capable of being anchored on the other side to a single anchoring point (4) in the installation environment, the structure comprising at least two parallel casings (5) containing adjustable ballasts, said casings (5) being in installed at the bottom of each of the lateral face (7) of the structure (2), in that the cage or cages (1) is/are square or rectangular, and in that the upper portion of the installation constitutes a handling bridge providing access to the cages.
