The article discusses the construction of four underwater tunnels using precast concrete elements. These tunnels include the Parana-Santa Fe road tunnel, the Elba road tunnel in Hamburg, the Conveyor Bakar tunnel in Yugoslavia, and the Karamoej pipeline tunnel in Norway. Each tunnel was built using different methods, such as in soil or on piles. The key findings highlight the technical and technological solutions used in constructing these tunnels, showcasing the diverse approaches taken to achieve successful underwater tunnel construction.