The study area in this report was located along the Chonburi coastline of Thailand from Ban Suan to Bang Lamung spreading over a 50 km distance. This area constituted mostly the industrialized area, the shipping area and the tourism area. Radioactivity levels from the natural radionuclides and the fission products before Fukushima Daiichi disaster especially l-131. Cs-134 and Cs-137 were The evaluat .The data may be used as a guideline for background levels of radionuclides in the marine sediments.