The versatility of marble has made it a favored material in construction, architecture, and the creation of statues, utensils, and antiques. Its use spans various civilizations, with many marble artifacts discovered in ancient sunken cities. To address the deterioration of these sunken artifacts caused by seawater salinity, pollution, and microbiological factors, research is focusing on their preservation in underwater museums, enhancing their display's appeal and artistic realism. This study replicates similar conditions by submerging marble samples in a marine environment, comparing untreated samples to those coated with cod liver oil. The oil is chosen for its hydrophobic and antimicrobial properties, making it an environmentally friendly preservative. The results indicate that samples coated with cod liver oil demonstrated higher fracture loads and enhanced structural integrity compared to uncoated samples. The uniaxial compression test showed a significant difference, with coated samples having a fracture load of 146.5 KN compared to 117.5 KN for uncoated samples. Scanning Electron Microscopy revealed fewer fractures, smaller pore spaces, and less failure in coated samples. Additionally, X-ray diffraction showed the presence of halite in uncoated samples, which was absent in coated samples, underscoring the protective effect of cod liver oil. Conversely, the coated samples demonstrated effective water resistance and protection from biological and chemical degradation, validating the hypothesis that cod liver oil is an effective preservative. The study strongly recommends using cod liver oil to coat submerged marble artifacts, ensuring their protection from underwater deterioration and aiding in their long-term conservation.