A Day Trip to Sarushima, Tokyo Bay’s Only Natural Island

Sarushima, which translates to “monkey island” in English, is the only natural island in Tokyo Bay. The uninhabited island located off Kanagawa Prefecture is easily accessible by ferry from Yokosuka. A great mix of history and abundant nature, it offers the perfect respite from the hustle and bustle of Tokyo.

History of Sarushima

Contrary to its name, there are no monkeys on Sarushima. But the island, once fortified, is rich in history, with ruins of bunker tunnels and gun batteries still remaining.

Arriving at Sarushima, "adventure island"

The island apparently earned its name from a legend that the 13th-century priest Nichiren was guided to safety by a white monkey when his ship washed ashore on the island in a storm.

Bunker tunnels on Sarushima

In the early 1800s, the Tokugawa Shogunate (1603-1867) built military fortifications on the island which still remain today in the form of excavated earthen tunnels, a barrack, and an ammunition depot. The fortress also played a critical role during World War II. Most of the structures, however, are now covered with moss and plants as nature slowly reclaims the island.

Moss on the walls of ruins on Sarushima

Things to do

Sarushima is quite small and can be explored on foot in around an hour or two. There are 30-minute and 60-minute guided tours available if you are interested in learning more about the history of the island. Both cost 500 yen and are only conducted in Japanese.

Directions on Sarushima

Even without the tour, you can soak up the luscious greenery and fresh ocean breeze as you explore trails through bamboo forests and bunker tunnels.

Walking around Sarushima

Make your way to an observation point where you can get sweeping views of Tokyo Bay and the skyline beyond. On clear days, you may even glimpse Mt. Fuji on the horizon.

View of Tokyo Bay

In the summer, the island is popular spot for beachgoers, with a small sandy stretch of beach near the pier that offers barbeque grills and umbrellas for rent. In other months it is probably a bit too cold to swim.

Sandy beach on Sarushima

There is one cafe on the island, but keep in mind lines can get quite long around lunchtime. So you might be better bringing your own food or waiting until you get back to the mainland.

Getting to Sarushima

From Shinagawa Station, take the Keikyu Main Line to Yokosuka-Chuo Station (around 1 hour). From there, walk 15 minutes to reach Mikasa Pier. Boats to Sarushima leave every hour from 9:30 am until 4:30 pm in March to October, and until 3:30 pm in the colder months. The journey takes around 10 minutes.


It costs 2,000 yen to visit Sarushima (1,500 yen for the round-trip ferry plus 500 yen island landing fee).

Ferry that links Yokosuka to Sarushima

Up until June 18, 2024, you can get a discounted 1,700 yen deal if you purchase an e-ticket from the official website. (Japanese only) Recommended, as you can directly board just by showing the ticket on your phone on the day.

On the way to Sarushima

Check out the archives more day trips ideas from Tokyo.

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