The current study investigates the classification and sources of radiation in the ocean, tackling an important issue of marine environmental science. Radiation in seawater comes from both natural and manmade sources, which have a substantial impact on marine ecosystems and human health. Natural sources include cosmic radiation and naturally occurring radioactive elements like uranium, thorium, and potassium isotopes. These elements enter the marine environment via geological processes and terrestrial drainage. Anthropogenic sources include nuclear weapons testing, nuclear accidents, and discharges from nuclear power plants and medical facilities. The study divides marine radiation into three types: alpha, beta, and gamma radiation, each having unique features, penetration capacities, and biological effects. Alpha radiation, which has poor penetration but a high ionization potential, poses severe biological dangers when consumed or inhaled by marine species and then people. Beta radiation, which can penetrate the skin but is less ionizing than alpha particles, largely impacts the marine food chain and human health through bioaccumulation and biomagnification. Gamma radiation, which is particularly penetrating and ionizing, poses significant environmental risks, affecting deep-sea ecosystems and pelagic animals.