NYK Maritime Museum

A pretty interesting museum, particularly for the price*. I actually paid to go in the museum because I wanted to see the building’s interior. (It’s a fairly rare neoclassical structure, which I think dates to the 1930s.)
The museum has displays related to NYK, a longstanding Japanese shipping company that handled mail and goods, as well as running a line of passenger ships. The displays on the old passenger ships, including interiors and furnishings, were most interesting to me, but if you’ve got a kid or two in tow or are a kid at heart, you might prefer the models of the big container ships and the like.
You can combine your visit with an exploration of the 1930s passenger ship Hikawamaru, off Yamashita Park. It’s mostly been restored back to its 1930s appearance and has displays inside as well. It’s a bit of a hike from the museum (maybe 15 minutes) but you can do that mostly along the waterfront, passing Osanbashi Pier, in keeping with the shipping theme.
All in all, a pleasant way to spend an hour on a day that’s a little too rainy or sunny or cold or hot. Happy sails to you!
(*250 or 400 yen depending on your age – they have combination tickets that allow access to the Hikawamaru as well.)