The city of Atami is only about a 45 minute ride on the infamous bullet train from Tokyo Station, however, it is world's apart. Atami probably had its economic peak about 30 years ago, but given its close proximity to Tokyo it is great place to go if you want to see visit a clean & enjoyable beach.
The town is built on a large hillside so if you don't enjoy walking up and down slopes, you may need to take a taxi. Fishing is still popular and local catch can be found in all of the supermarkets, restaurants & souvenir stands. I am not a big fan of dried fish (of any variety) but it is popular in Japan.
Atami is a natural hot spring area and hot water is bubbling up from the ground everywhere. The bad news is that the town is sitting atop a cauldron - hope it doesn't explode in my time.