Even if you're on the fence about aquariums, Kaiyukan is pretty impressive - we're talking about one of Japan's best. Yes, it gets seriously crowded (like most popular spots in Japan), but there's a reason for that. The way they've designed it is clever - you start at the top and spiral down through different ocean habitats, with that massive central tank housing whale sharks!

Pro tip: Book your tickets online - this isn't the kind of place where you want to be standing in line with everyone else. The crowd situation can get intense, especially around the most popular exhibits, so having your tickets sorted in advance is crucial.

For anyone wrestling with the ethics of aquariums: while that's a personal decision, Kaiyukan does seem to put a lot of effort into education and conservation. Plus, its location in Tempozan Harbor Village means you can combine it with other activities (like that Santa Maria cruise we laughed about) to make a full day of it.