Shimoda Floating Aquarium sits in Wakanoura Bay, south of the central port. Its floating enclosures and dolphin programs make it more place-specific than a standard city aquarium, especially for families or travellers with a half-day to fill after the beach.
It is best paired with Shimoda Park or the harbour walk. If your time is tight, Perry Road, Ryosenji, and Shirahama should come first.