A highway rest stop in the middle of the sea between Tokyo Bay and Chiba
Umihotaru is the world's only highway rest stop that sits on top of the sea. It is part of the Aqua-Line, a highway that runs underneath Tokyo Bay from Kisarazu in Chiba to Kanagawa Prefecture. As you drive through the tunnel, it rises again to the surface at Umihotaru, and you can stop to take in the view.
Quick Facts
The rest stop has a unique parking structure that houses five floors of restaurants, shops, and observation decks
Umihotaru generates electricity from the near-constant winds blowing across the Tokyo Bay
How to Get There
Umihotaru can be reached from either side of Tokyo Bay (Kawasaki or Kisarazu).
There are buses that go to the island departing from Kawasaki and Kisarazu stations. Make sure that you check the schedule before planning your trip.
If you are driving from Tokyo, Yokohama , or Kawasaki , connect to the Aqua-Line by the Bayshore Route or National Route 409 at both the Kawasaki Ukishima junction and Ukishima interchange. From the Chiba or Kisarazu area, the Aqua-Line connects to the Aqua Renraku Expressway and National Route 409 at the Kisarazu Kaneda interchange.

The world's most unusual parking lot
Umihotaru's name means sea firefly. This huge structure has five floors of observation decks, restaurants, and shops as well as unusual architecture.
The fourth floor has shops and observation decks. The observation decks offer a windswept view of Tokyo like no other from its spot in the middle of Tokyo Bay. You can see the city's skyline and many of its iconic buildings as well as much of Chiba and Yokohama .


The observation decks also offer an up-close look at one of the giant cutters used to carve out the Aqua-Line's tunnel.

Complete range of facilities
The lower three floors, which are for parking, can accommodate about 500 cars and trucks. The third floor has a small museum on the construction of the Aqua-Line and Umihotaru. It is also the home of the Bay FM and Inter FM radio stations.
A tower in the middle of the island supplies air to its facilities. It powers the artificial island using the continual winds of Tokyo Bay, earning it the name Kaze No To, which means Tower of Wind.
If you are taking the Aqua-Line, Umihotaru is a must-see attraction. You can spend quite a bit of time there eating, shopping, and taking in the views.