Egypt is planning for the construction of electricity-generating nuclear facilities to accommodate population growth and increased industrial and domestic demand for electric energy. This study aims to predicate the radiological exposure levels of marine biota such as Crustacean, Mollusc-bivalves, and Zooplankton, which may be occurred due to exposure to the radionuclides released from the discharge of the cooling water system of the suggested Egyptian nuclear power plant (ENPP) on the northern coast of the Mediterranean Sea in Egypt by using the ERICA and RESRAD models. To achieve this study, eighteen water samples were being collected from the three selected sites (Alam El Roum, Minaa-Alhasheesh, and El Alamein) at the north Mediterranean coastal zone of Egypt, and their activity concentrations were measured by using gamma spectrometry. The calculated absorbed dose rates of the selected biota by using both ERICA and RESRAD tools were below the ERICA 10 microgray/h screening value. The results of both two models showed that the biota concentration guide BCG and the risk quotient QR of the selected biota have complied with the recommended limits. On the other hand, the results showed that the least radiological impact of the once-through cooling system using the ERICA model was at a distance of 1 Km starting from the cooling discharge point to the shore and up to 2 km to the receptor inside the Mediterranean Sea. The results of the two models indicated that the minimal radioactive effect of the once-through cooling system on the selected biota in Mediterranean waters.