A method for the autonomous anchoring of foundations for offshore structures, built on a floating dock and capable of being towed to their final location, consisting of a self-floating concrete caisson, provided with internal vertical cells, closed at the top by means of a slab that covers all or almost all the cells in which it is divided, which are interconnected with each other and equipped with emptying and filling devices (5, 7) that allow the regulation of the ballast level for anchoring when they are filled with seawater, comprising a preliminary stage: constraining the foundation, fastening and mooring with at least three tugboats pulling radially on the foundation to be anchored from at least 3 different directions, spaced apart at a similar angle, so that once the foundation is vertically located on its final installation site, it is kept in the same vertical position throughout the entire anchoring process, characterized in that it also comprises the following stages a) a preliminary stage of connecting the different sensors (6, 8) needed for controlling the operation with a control unit receiving the information from said sensors, preferably located on the emerged platform of the foundation that remains above sea level once the foundation has been totally anchored, said control unit integrating means of communication with the directional system between the tugboats, and means of communication between the GPS stations and a fixed GPS reference base located at a fixed point next to the installation location of the foundation; as well as the implementation of a decision-making support system, which enables visualizing and controlling the progress of the anchoring process; b) gradual and controlled sinking of the foundation until it is slowly submerged, remaining in a neutral position under the water and subsequent anchoring of the same in a next to neutral seaworthy condition until it reaches its position of installation on the seabed; c) final ballasting of the foundation, flooding of all the cells that the foundation incorporates and disengaging the tugboat lines. constraining the foundation, fastening and mooring with at least three tugboats pulling radially on the foundation to be anchored from at least 3 different directions, spaced apart at a similar angle, so that once the foundation is vertically located on its final installation site, it is kept in the same vertical position throughout the entire anchoring process, characterized in that it also comprises the following stages a) a preliminary stage of connecting the different sensors (6, 8) needed for controlling the operation with a control unit receiving the information from said sensors, preferably located on the emerged platform of the foundation that remains above sea level once the foundation has been totally anchored, said control unit integrating means of communication with the directional system between the tugboats, and means of communication between the GPS stations and a fixed GPS reference base located at a fixed point next to the installation location of the foundation; as well as the implementation of a decision-making support system, which enables visualizing and controlling the progress of the anchoring process; b) gradual and controlled sinking of the foundation until it is slowly submerged, remaining in a neutral position under the water and subsequent anchoring of the same in a next to neutral seaworthy condition until it reaches its position of installation on the seabed; c) final ballasting of the foundation, flooding of all the cells that the foundation incorporates and disengaging the tugboat lines. a) a preliminary stage of connecting the different sensors (6, 8) needed for controlling the operation with a control unit receiving the information from said sensors, preferably located on the emerged platform of the foundation that remains above sea level once the foundation has been totally anchored, said control unit integrating means of communication with the directional system between the tugboats, and means of communication between the GPS stations and a fixed GPS reference base located at a fixed point next to the installation location of the foundation; as well as the implementation of a decision-making support system, which enables visualizing and controlling the progress of the anchoring process; b) gradual and controlled sinking of the foundation until it is slowly submerged, remaining in a neutral position under the water and subsequent anchoring of the same in a next to neutral seaworthy condition until it reaches its position of installation on the seabed; c) final ballasting of the foundation, flooding of all the cells that the foundation incorporates and disengaging the tugboat lines.