I'm taking my girlfriend to Tokyo, Japan in July and we have are planning to take a trip to Disney World and Disney Sea but we would also love to spend one day in a more water basted park in the hot weather that's in Tokyo for July.

What would be the best tip for a water park close to Tokyo (we'll be staying at the Conrad Tokyo for our trip) that we could visit? We don't want something rather small and mediocre but something that feels like a water world where we can spend almost, if not even a whole day.


Any recommendations?