Natural radiation is omnipresent everywhere on the earth, and humans cannot avoid it. Natural radiation is a critical aspect in understanding the health issue and predicting the existence of radionuclides. Because the ocean is the source of all materials, and due to the fact that water from everywhere is submerged in the ocean through river networks, the ocean will contain varying radiation doses in every site. This book has information about radiation status near the ocean in all areas on Earth. There are five oceans, namely: the Atlantic, Pacific, Indian, Arctic, and Antarctic Oceans. This book is a valuable resource of its kind for indicating the radiation status in all types of oceans. The outcomes of this book are extremely valuable to people in a variety of fields, including health sciences, material sciences, radiological fields, environmental science, oceanology, water world, and so on.