The invention concerns a device for automatically and rapidly locating (10) a person or an object at sea in poor meteorological conditions, comprising a radio wave transmitting device (20) provided on the person or the object and a reception device (30), provided in a boat, and designed to receive directly said waves and to process them without any other intermediary than the radio link (40) established between them. The transmitting device (20) comprises a transmitter (21) supplied by a power source (23), and delivering a radio signal to an antenna (22). Said transmitter is activated by an actuating member (24). The reception device (30) consists of a receiver (31) for the signal transmitted by the transmitter (21) and picked up by an antenna array (32) co-operating with an antenna switch (33). The antenna array (33) is connected to the receiver (31) whereof an output is connected to said unit processing (34) the received signal. A display unit (37), connected to said processing unit (34) via a user interface (35), enables the display of the information delivered by said unit (34). An audio warning (36) is connected to the activation of the transmission device (20).