Noshappu Cold Water Aquarium focuses on the cold seas around northern Hokkaido. It is a small aquarium, but the outdoor tanks with seals and penguins give it enough character to be worth considering, especially with children or in poor weather.
The indoor tanks show species from northern and southern marine ecosystems, while feeding times bring most visitors outside. Pair it with Cape Noshappu or the nearby science centre rather than treating it as a full-day attraction.