Kagoshima City Aquarium (io World)

Kagoshima City Aquarium, branded as io World, sits at the edge of Kagoshima Port near the Sakurajima Ferry Terminal, making it a natural pairing with a morning ferry crossing. Opened in 1997, the aquarium is one of Kyushu's largest marine facilities, with exhibits organised to represent the marine ecosystems of the waters surrounding Kagoshima Prefecture — from the temperate bay waters to the deep-sea trenches of the East China Sea. The centrepiece is a 10-metre deep, 1.5-million-litre main tank housing whale sharks, manta rays, and a large school of open-water schooling fish observed from multiple levels. The Kuroshio Current exhibit recreates the warm Pacific surface current that sweeps past Kagoshima and influences species distribution all the way to Japan's southern islands. A separate open-air tank at the rooftop level allows dolphin observation, with scheduled feeding and health check presentations throughout the day. The jellyfish gallery is a highlight for visitors of all ages — dozens of species displayed in cylindrical and ring tanks with coloured backlighting. A touch pool with sea urchins, starfish, and small reef species is available on the lower floor and is particularly popular with younger visitors. The aquarium's proximity to the Sakurajima ferry gives it a practical advantage as a rainy-day option or pre- and post-ferry activity, and its marine scope reflects the extraordinary biodiversity of waters between Kagoshima and the Nansei Islands.