Abstract: In a method and a device for tracking an object (2a), especially a subsea object, while utilizing a mother vessel (1) or an intermediate craft (101) equipped with sonars (3a) for the transmission and reflection of searching rays (3b, 3n) which on a display on the vessel (1) indicate one or more objects (2a) in the subsea search area, there is provided a searching unit (2) which is controlled from the vessel (1), and which comprises at least one transponder/responder (10, 13) or the like, for the transmission of signals corresponding to the searching rays (3b). The signal(s) is registered on the display on the mother vessel (1) and is used for guiding the searching unit (2) towards a selected object (2a) along the searching rays (3b, 3n) of the sonars.