Hakkeijima Sea Paradise
Hakkeijima Sea Paradise is just south of Yokohama. This is a great place to spend the day for the whole family. Multiple aquariums with hundreds of varieties of sea life. Total number of sea life is well over 100,000. From sea turtles to penguins and numerous other attractions you may be surprised to see in Japan such as beaver, otters, and even some walrus.
Access is via the excellent rail system or by car. Detailed access instructions are on their website here: