In this study, surface sediment samples from the North Cyprus East coast of the Mediterranean Sea were collected to determine the concentrations of three main natural radionuclides (226Ra, 232Th, and 40K) using a high-resolution HPGe gamma-spectroscopy system. The activity concentrations of 226Ra, 232Th, and 40K in the selected sediment samples ranged from 11.5 to 31.6, 11.8 to 24.9, and 391.7 to 1014 Bq kg−1 dw (dry weight), respectively. The concentration distribution analysis showed that the kurtosis statistics parameter was negative, and the concentration distribution was less peaked than the normal curve. The mean activity concentrations of 40K (628.1 Bq kg−1) in the sediment samples was higher than the worldwide average (420 Bq kg−1) concentration. The radium equivalent activity, external hazard, internal hazard and gamma activity concentration indexes were calculated to assess the pollution and risk level of radionuclides. The radiological risk assessment indicated that observed values were below the threshold values. • Natural radioactivity concentration in the marine sediments was measured. • Investigation of radiological hazards due to natural radiation in study are • Average activity concentration of 40K was higher than the worldwide average concentration. • The radiological hazards were found less then recommended value. [ABSTRACT FROM AUTHOR]