Abstract: The subject of the examinations carried out is hydroacoustic noise in coastal zones. Under these conditions natural noise and the noise from moving vessels affect each other, as well as interference from industrial infrastructure located close to the coast. Both natural noise and noise caused by human activity affect the detection and identification of noise sources in these conditions. Experiments have been performed by the mobile measuring module in the Gulf of Gdansk. This showed that it can extract spectrum components, based on the results of underwater noise. These components allow the detection of moving objects. The collected database of measurements enabled the comparison of one-third-octave spectra of three different ships. The components specific to the type of vessel could extracted as a result of comparison. Consequently one of the three tested vessels could be identified.