Blue street is the center of life in Yokosuka for sailors and their wives. It's a great place to go shopping and to people watch. The street actually has blue stones mixed in with the usual black. The sidewalks are lined with benches that bear life-sized statues of Jazz musicians. Why? I have no idea.
While you're there make sure to visit Mighty Soxer, halfway down the street on the right hand side. They carry nothing but socks and slippers for both men and women. It makes a great souvenier to send home. There's also a really charming stationary shop on the left.
At the end of the street on the right side is the Yokosuka Ke-Kyuu train station.
This was by far the highlight of my visit to Yokosuka.
Permanently berthed in Mikasa park is the old ship Mikasa, which served in the Russo-Japanese war of 1904-05. The museum housed inside the ship gives an interesting account of what happened, although typically for Japan with some revisionism.
Some of the quarters have been refurbished at some cost to give you an idea of what ship life was like in those days, with luxurious officers quarters, and more spartan areas for the others.
The Miskasa Battleship is THE must-see in Yokosuka. You buy tickets (no more than 500 yen, I think it was 300 yen for military) at little machines in the park, and they give you a brochure in English when you enter. This was Admiral Togo's flagship during the Russo-Japanese war and is wonderfully restored!
The park is awesome too (it's free). It's right on the harbor with great views. There are fountains, including one that has a light/music show, I believe it goes every hour or so mid-day, there are signs in English in the park so you can plan your ship-visit around it.
For Japan, it's not very crowded at all. It's a nice place to relax with a book, or write some postcards home.
A small and cozy museum located just in front of the beach, it's Yokosuka Museum.
You can check the exhibition schedule in their web site, but unfortunately only Japanese.
The architecture which makes this cozy atomosphere is worthy to mention. The wooden floor with cherry tree is well polished always, the sun is shinng into the gallary from the sunlight. You can go up to the roof and enjoy the view of Tokyo Bay with a free telescope.
As you see, I can recommend you to visit there especially on a sunny day. You can see the wonderful ocean view from the museum or sit down on the beach in front of the museum. If you are tired of going around the busy city in Japan but you want to do something other than staying at hotel or home, it should be one of the best way to take rest and a relax time.
On a rainy day,,, you may not want to go there taking a bus all the way.
Also I recommend you to take a lunch buffet at the Keikyu Kan'nonzaki Hotel, 5 min walk from the museum.