Remote-controlled buoy, including a main body for protection and buoyancy, a rope provided at one end with dismountable connecting means (12.1) and, at the other end, connected to a winding device, provided on the inside of said main body, characterized in that it comprises: - a rotating shaft (13.1) of said winding device, which is connected to said other end of said rope and is cinematically connected to motor means (14; 24) to be rotated; - automatic stoppage means for said motor means (14; 24) with rope wound on said shaft (13.1), so as to prevent, in the rest position, the rotation of said shaft (13.1) in the direction of unwinding of said rope whereby said automatic stoppage means comprise ratchet stoppage means, urged by their own elastic means to engage with said shaft (13.1), when said rope is fully wound on said shaft (13.1), and selectively returned against the action of said own elastic means, by means of actuator means; - remote-control means for said motor means (14; 24) that, in an operating position determined by said remote-control means, rotate in the direction of unwinding of said rope, and in that said remote-control means comprise, in said buoy, electric battery power supply means (16.2) and electronic control micro-circuit means, for the powering and selective control of said actuator means, electro-magnetic means respectively, receiving electronic means of coded electrical signal, operatively connected with said electronic micro-circuit means and, separate from said buoy, remote-control transmitter means (16.1) and emitter means (16.3) for a coded electrical signal corresponding to the coded electrical signal of said signal receiving means, so that said buoy sinks together with a retrieval cable, i.e. together with a fixed mooring to be placed on the sea-bed, one or other being connectable thereto by means of said dismountable connecting means (12.1), when said remote-control means are operated and determine the said operating position of said motor means (14; 24), it returns to the surface automatically due to the hydrostatic thrust, while said rope is unwound from said rotating shaft (13.1) and, in the case of connection with said fixed mooring, floats in a stationary manner on the surface, whereas, if it is connected to said cable, it can be retrieved onto a vessel, through the intervention of an operator, by dragging the cable together with said wound rope, and it is released from said cable by disengaging said dismountable connecting means (12.1), fixed to said other end of said rope, which is re-wound onto said shaft (13.1) by means of said motor means (14; 24). - a rotating shaft (13.1) of said winding device, which is connected to said other end of said rope and is cinematically connected to motor means (14; 24) to be rotated; - automatic stoppage means for said motor means (14; 24) with rope wound on said shaft (13.1), so as to prevent, in the rest position, the rotation of said shaft (13.1) in the direction of unwinding of said rope whereby said automatic stoppage means comprise ratchet stoppage means, urged by their own elastic means to engage with said shaft (13.1), when said rope is fully wound on said shaft (13.1), and selectively returned against the action of said own elastic means, by means of actuator means; - remote-control means for said motor means (14; 24) that, in an operating position determined by said remote-control means, rotate in the direction of unwinding of said rope,