Hamada “three lucky things” course
This course starts off at Tatamigaura, rock pools full of little creatures. It's a great way to spend an hour or so with kids, especially if you bring a net and a tank to scoop up some creatures for a short time before returning them to the sea. Then head off to Aquas, the aquarium near the beach. (If you live within driving distance get the year-long season ticket.) Try the fish centre (Osakana centre) for lunch and Yuhi Park to buy souvenirs, or see the sunset. The pdf with more details can be downloaded below.
On the first floor of Aquas, there is a really big tank called the Sea of Myths. The reason why it was named so is because a lot of Japanese myths originated in Shimane. There are many varieties of sharks, and some other sea creatures such as rays, a huge sea turtle and so on. And there are some benches! If you are tired or watch it for a moment, these benches are great. You can sit down and enjoy watching the sea creatures. If you bring kids, point out the UV lights on the back wall of this area; they might enjoy seeing light-coloured clothing glow in dark.
After the shark tank, you can walk through the shark tunnel. You can enjoy watching their stomachs, and signs of the wall tell you how to differentiate male and female sharks.
If you book the "backyard tour"--a kind of behind the scenes look at the aquarium--in advance, you can see inside this tank from the top. They also do sleepovers at the aquarium for parents and kids in the summer vacation. Check the details on their webpage.