The invention relates to a method and to a device for producing a boat-type body (10) of a water sport device. According to the invention, a rotating frame (12), which is pre-formed about an access opening of the boat-like body (10), is arranged on an inner side of a negative mould. The outer shape of the boat-type body (10) is predetermined, essentially, by the innerside of the negative mould. The boat-like body (10) is produced in the inner side of the mould by means of a thermoplastic shaping method. During the shaping process, at least one part of the surface of the rotating frame (12) is in contact with the boat-like body (10) which is formed by the thermoplastic shaping method. The invention also relates to a water sport device.