• The Tokyo Bay Aqua-Line is a 15.1 km long expressway that crosses Tokyo Bay, connecting Kisarazu City, Chiba Prefecture, and Kawasaki City, Kanagawa Prefecture. The Aqualine consists of undersea tunnels and bridges, of which about 9.5 km are undersea tunnels and 4.4 km are bridges. 1997 saw the opening of the Aqualine, which has dramatically improved traffic convenience by allowing travelers to come and go between Kanagawa and Chiba without having to make a major detour around Tokyo Bay.
• ① Umihotaru Parking Area: Located on a man-made island in the middle of Tokyo Bay, this parking area is a popular tourist spot with 360-degree views of the ocean. There are restaurants, souvenir stores, and an observation deck.
• ②The long tunnel that runs through the bottom of Tokyo Bay was constructed using the most advanced civil engineering technology. In particular, tunnels excavated using the “shield tunneling method” are among the largest in the world.

Umihotaru is a parking area on a man-made island located right in the middle of the Tokyo Bay Aqualine, with a unique location surrounded by the sea in 360 degrees, giving it the feel of a floating resort on the sea. Highlights and things to do in Umihotaru: Observation deck with spectacular views There is an observation deck overlooking Tokyo Bay, where you can see Mt. Fuji, Yokohama's Landmark Tower, and the Boso Peninsula if the weather is nice. ️ Gourmet Spots There are many restaurants and cafes where you can enjoy popular menus such as seafood rice bowls, ramen noodles, and sweets. Local gourmet food is also recommended. ️ Souvenirs/Shopping There are many souvenirs that can only be purchased here, such as specialty products of Chiba and Kanagawa, and sweets and goods exclusive to Aqua-Line. Photo Spot There are many spots where you can take pictures, such as the “Bell of Happiness” and monuments and objets d'art of the Aqua-Line construction.