The Osaka Aquarium Kaiyukan is an aquarium located in the ward of Minato in Osaka, Osaka Prefecture, Japan, near Osaka Bay. When it first opened, it was the largest public aquarium in the world. It is a member of the Japanese Association of Zoos and Aquariums. The aquarium is about a five-minute walk from Osakako Station on the Osaka Municipal Subway Chūō Line, and is next to the Tempozan Ferris Wheel.