Two to three hours by train from Tokyo station, the Izu Peninsula offers numerous hot springs and seaside resort towns, so it is a popular day trip and weekend get-away destination for many Tokyoites. The peninsula is also famous for being one of only a couple areas in Japan where wasabi is widely cultivated.
Atami and Shimoda are perhaps best known, but there are dozens of less renowned towns on both sides of the peninsula, and in the interior, with inviting attractions.
You can get in by taking Japan Railroad's Odoriko service from Tōkyō or Ikebukuro to Izukyū-Shimoda or Shūzenji. There are also express buses that operate to destinations on the Izu Peninsula.
Izu Peninsula is recognized in the scuba diving community as the most popular destination for mainland Japan diving. The East Coast of Atami is most popular with dive operators for its accessibility and infrastructure, while the West Coast's sites are largely unspoiled, safeguarded from weekend crowds by its remote destination and lack of train stations.