Unlocking the behavior of uranium in seawater requires an understanding of its chemical speciation, primarily as a highly soluble uranyl ion (UO22+), which stabilizes complexes with phosphate, sulfate, carbonate, etc., to increase mobility. Despite its high solubility, uranium can precipitate as uranite under reducing conditions. The redox mechanism affects its speciation; reducing and oxidizing conditions produce less soluble U(IV) and prefer U(VI). Uranium may adsorb onto particles and sediments, especially in lower settings, and then be absorbed back into the water when environmental conditions change. Because of its bioavailability, it may be hazardous to people, aquatic organisms, and other creatures. Geographical and temporal fluctuations in seawater river supplies, hydrothermal vents, and changes in seawater chemistry influence uranium concentrations. The industries that release uranium-contaminated water are metal mining, nuclear power plants, phosphate fertilizer manufacturing, and uranium mining. Thus, the increased need for military, industrial and agricultural activities will result in higher uranium concentrations in nearby water bodies. Furthermore, using too much groundwater might lead to a higher uranium content. Human activities, including agricultural practices involving the use of chemical fertilizers (containing phosphate, potassium, etc.), residues from uranium mining, nuclear testing, etc., increase uranium levels in water bodies. High levels of uranium in the ocean cause detrimental bioaccumulation in marine life, disrupting ecosystems and posing risks to reproductive and renal systems; control and monitoring are key because consuming contaminated seafood and long-term exposure to uranium radiation increase the risk of kidney damage, cancer, and radiation sickness in humans. Comprehending these actions is essential for controlling uranium pollution in wastewater and safeguarding the public’s health. This chapter focuses on revealing uranium behavior in polluted water.