Built in July 1958 as a "marine venue" for the Hokkaido Grand Exposition, the aquarium began operations in 1959 as the Otaru Municipal Aquarium, and with the completion of the new building (now the main building) in 1974, it was managed by the Otaru Aquarium Public Corporation, a third-sector corporation. The aquarium consists of the main building, which exhibits a wide variety of fish and shellfish, the Dolphin Stadium, which features dolphin and sea lion shows, the Marine Park, where seals, walruses, sea lions, penguins, and other animals are kept, and the amusement park, Otaru Shukuzu Marine Land. The marine animal park is located in a natural cove, where seabirds also fly in. Wild sea lions and largha seals sometimes stray into the park from the coast and are kept there. The aquarium is usually open from spring break in March (previously April) to November, but has been open in winter since 2006 in conjunction with the Otaru Snow Light Path and the
Sapporo Snow Festival. In 2023, Otaru Aquarium was entrusted with the breeding and operation of AOAO SAPPORO, an aquarium that opened on the fourth to sixth floors of the tower building in
Chuo-ku, Sapporo. • 1959 - Inaugurated as the Otaru Municipal Aquarium. • 1983 - Dolphin Stadium is completed. == Research and conservation ==