Abstract <p>Assessment of the elastic properties of bottom sediments is necessary for studying the engineering-geological conditions of an investigated water area. One of the methods for obtaining the elastic properties of sediments is ultrasonic research. Ultrasonic studies were performed on samples of poorly consolidated bottom sediments represented by clays and physical clays of various mineral compositions in Rugozerskaya Bay of the Kandalaksha Gulf in the White Sea in June 2024. The samples were taken by a gravity corer at 11 stations that were preliminarily selected on the basis of the analysis of seismic-acoustic profiles. In total, we took 25 samples (cores), and their sampling depths ranged from 0.2 to 2 m. Ultrasonic measurements of velocities of compressional and shear waves were performed on 88 samples from the taken cores. We determined the compressional wave velocity based on the first arrival times at a fixed measurement base (length of the sample) and the shear wave velocity, using the travel-time curve of the direct shear wave on the seismogram obtained by varying the measurement base. Ultrasonic studies were performed using piezoelectric ceramic transducers for compressional and shear waves with frequencies of 60 and 100 kHz, respectively. The resulting ranges of wave velocities in the sediments represented by physical clays and clays were from 10 to 40 m/s for shear waves and from 1000 to 1800 m/s for compressional waves.</p>