It’s a park with a beach (not for swimming I don’t think) and this area has a museum and aquarium too. Then the island of Takeshima, which is a collection of shrines on top, and then you can walk around the island and get down on the island beaches. You get to the island by bridge and walk under a huge stone Torii that predates Showa and Meiji, I think.

There are lots of stairs, so it’s not really accessible to those with mobility restrictions, but I think you sold be able to get someone on wheels across the bridge and onto the island at least.