Carbon stocks are the carbon content stored below and above ground in a system. Soil is one of the places with the highest potential for carbon storage. Carbon stocks come from organic matter from the decomposition of animals, plants, and other organisms was his study aimed to analyze and estimate soil properties and soil carbon stocks in the Marine Science Techno Park (MSTP) area. The research was conducted at MSTP in Teluk Awur, Jepara. The research site was divided into two stations: terrestrial (Station 1) and mangrove (Station 2), with three sampling points at each station. Soil samples were taken to a depth of 40 cm and analyzed for bulk density (BD), soil organic carbon content, SOC stock, and CO2 equivalent. Bulk density values obtained in terrestrial soil were lower (0.54 to 0.66 g/cm3) compared to mangrove soil (0.72 to 0.83 g/cm3). The organic carbon content obtained in terrestrial soil was 9.15%, and in mangrove soil (0.41% to 0.60%). The terrestrial SOC stock was significantly higher (113.76 tons/ha) than the mangrove (15.45 tons/ha). The total SOC stock in MSTP is 602.32 tons, with terrestrial lands making the most significant contribution. CO2 equivalent storage potential is 2210.52 tons, mainly from terrestrial ecosystems. Terrestrial lands have more extensive SOC stocks due to higher organic matter inputs and differences in soil structure. This underscores the importance of effective management practices such as reforestation to increase carbon storage.