Approximately 1 kilometer offshore from the coast, it is the world's first ice-covered sea underwater observation tower soaring at the tip of Monbetsu Port No. 3 Breakwater. It possesses both tourist facilities and research observation facilities from the seabed floor to the 3rd floor. Its height is 38.5 meters above sea level, and 7.5 meters underwater. Precisely because it is above sea level, there is a 3rd floor observation room where you can enjoy a 360-degree view, a 4D theater on the 2nd floor, and on the seabed floor, there are 11 large and small underwater windows and a mini aquarium where you can feed sturgeon, etc. Not only the winter drift ice, but also various ecological observations of marine life can be done throughout the four seasons. Furthermore, Monbetsu Port No. 3 Breakwater, which serves as the connecting path to the tower, is popular as a walking spot, with the nickname "Clione Promenade." Cafe "companio" is operating in the 3rd floor observation room.