Abstract: The invention relates to an underwater viewing device wherein a viewer can immerse the lower portion thereof into a body of water and view clear, undistorted images of objects which appear immediately below the underwater viewing device. The underwater viewing device is provided with a viewing tube having a plurality of opaque sides that project upwardly from a horizontal planar surface made of clear plexiglass. The opaque sides rise upwardly at a forty-five degree angle relative to the horizontal planar surface. This viewing tube is open at the uppermost end and permits viewers to look therein without the requirement of placing their head into contact with the viewing tube. Additionally, the viewing tube is not required to be covered as in prior art devices. The basic concept of the underwater viewing device is embodied in a hand held unit while there are also disclosed other applications such as air mattresses, inflatable boats and catamaran-type paddle-wheel boats.