Located in the Minato ward of Osaka, Japan, near Osaka Bay, the Osaka Aquarium Kaiyukan is a prominent public aquarium that opened in 1990. Constructed as part of a waterfront redevelopment project alongside the Tempozan Marketplace, it was the largest public aquarium in the world at the time of its opening. Situated next to the Tempozan Ferris Wheel, the facility is accessible via a five-minute walk from Osakako Station on the Osaka Municipal Subway Chūō Line.
The exterior of the building features three color schemes representing earth, water, and fire, along with an exterior fish mural. Designed under the leadership of architect Peter Chermayeff, the facility utilizes thick acrylic glass panels for its aquatic displays. To maintain water clarity, water circulates from the bottom of the tanks upward to collect floating waste, while oxygen is supplied through artificial waterfalls. The visiting route begins on the eighth floor, reached via an escalator, and gradually winds down to the fourth floor through various marine environments set to daytime ambient music.
The aquarium displays aquatic life across 16 main exhibit areas containing 27 tanks. The journey starts at the Aqua Gate tunnel tank before leading into the Japan Forest exhibit, which showcases native Japanese freshwater species alongside local forest plants. Additional zones replicate habitats around the Pacific Ocean's Ring of Fire, including the Aleutian Islands, Monterey Bay, the Ecuador Rain Forest, Antarctica, the Great Barrier Reef, the Seto Inland Sea, and the Japan Deeps. A dedicated jellyfish gallery displays species such as moon jellyfish and northern sea nettles.
At the center of the exhibit path is the Pacific Ocean tank, holding 5,400 cubic meters of water. This large exhibit houses whale sharks—the aquarium's most popular species—alongside reef manta rays, Pacific bluefin tuna, and scalloped hammerhead sharks. Visitors can also view ocean sunfish, Japanese spider crabs, and various species of penguins and seals. An interactive zone features Arctic, Falkland Islands, and Maldives sections, allowing guests to view animals up close and directly touch stingrays and small sharks.
Beyond its public exhibits, the institution operates a specialized research center in Kochi Prefecture, conducting marine life surveys and studying the breeding and migration patterns of sharks and rays. The main complex in Osaka also includes a museum shop offering thematic merchandise.
See the full Osaka travel guide for where to stay, the best time to visit and the top things to do.