The Tokyo Bay Aqua-Line (東京湾アクアライン, Tōkyō-wan Akua-rain[8]), also known as the Trans-Tokyo Bay Expressway, is an expressway that is mainly made up of a bridge–tunnel combination across Tokyo Bay in Japan. It connects the city of Kawasaki in Kanagawa Prefecture with the city of Kisarazu in Chiba Prefecture, and forms part of National Route 409. With an overall length of 23.7 km, it includes a 4.4 km bridge and 9.6 km tunnel underneath the bay—the fourth-longest underwater tunnel in the world.[9]

Tokyo Wan Aqua-Line Expressway sign
Tokyo Wan Aqua-Line Expressway
The Tokyo Bay Aqua-Line highlighted in red
Route information
Length23.7 km (14.7 mi)
National Route 409
Major junctions
West endKawasaki Ukishima Junction
Shuto Expressway Bayshore Route
in Kawasaki, Kanagawa
Section 1
East endKisarazu Interchange
Ken-Ō Expressway in
Kisarazu, Chiba
Highway system
Tokyo Bay Aqua-Line

Tokyo Bay Aqua-Line (bridge section)
Tokyo Bay Aqua-Line (bridge section)
Coordinates35°27′47″N 139°52′31″E / 35.46306°N 139.87528°E / 35.46306; 139.87528
Carries4 lanes of National Route 409[1]
CrossesTokyo Bay
Other name(s)Trans-Tokyo Bay Highway
Total length
  • bridge: 4,384 metres (14,383 ft)[2]
  • tunnel: 9,600 metres (31,496 ft)
Width22.9 metres (75 ft)[2]
Longest span240 metres (787 ft)[3]
Piers in water42[2]
Clearance below29 metres (95 ft)[2]
Fabrication by
  • bridge: Yokogawa Bridge Corp.[4] and JFE Engineering[5]
  • tunnel:
Construction start1989
Construction cost¥1.4 trillion
Opened18 December 1997 (1997-12-18)
Tokyo Bay Tunnel
Umihotaru, where the bridge transitions to tunnel
Umihotaru, where bridge transitions to tunnel
  • 2 in use
  • 1 planned
StartUmihotaru Island
EndUkishima, Kawasaki, Kanagawa
No. of lanes2 (unidirectional) in each of 2 tunnels
Highest elevationsea level
Lowest elevation−45 metres (−148 ft)
  • 14.1 metres (46 ft) OD
  • 11.9 metres (39 ft) ID
  • 10.5 metres (34 ft) roadway



An artificial island, Umihotaru (ほたる, Umi-hotaru, "sea firefly," referring to Vargula hilgendorfii), marks the transition between the bridge and tunnel segments and provides a rest stop with restaurants, shops, and amusement facilities. A distinctive tower standing above the middle of the tunnel, the Kaze no Tō (, "the tower of wind"), supplies air to the tunnel, its ventilation system powered by the bay's almost-constant winds.

Tokyo Wan Aqua-Line.
Tokyo Bay Aqua-Line bridge.

The ¥1.44 trillion (US$11.2 billion) roadway opened on December 18, 1997, after 23 years of planning and nine years of construction.

The Tokyo Bay Aqua-Line shortened the drive between Chiba and Kanagawa, two important industrial areas, from 90 to 15 minutes,[10] and also helped cut travel time from Tokyo and Kanagawa to the seaside leisure spots of the southern Bōsō Peninsula. Before it opened, the trip entailed a 100 km journey along Tokyo Bay and pass through central Tokyo.

Tokyo Bay Aqua-Line Highway at night.

An explicit goal of the Aqua-Line was to redirect vehicular flow away from central Tokyo, but the expensive toll has meant only a limited reduction in central-Tokyo traffic.

Many highway bus services now use the Tokyo Bay Aqua-Line, including lines from Tokyo Station, Yokohama Station, Kawasaki Station, Shinagawa Station, Shibuya Station, Shinjuku Station and Haneda Airport to Kisarazu, Kimitsu, Nagaura station, Ichihara, Mobara, Tōgane, Kamogawa, Katsuura and Tateyama.



The cash toll for a single trip on the Aqua-Line is ¥3,140 for ordinary-size cars (¥2,510 for kei cars); however, using the ETC (electronic toll collection) system, the fare is ¥2320 (¥1860 for kei cars). The ETC toll is reduced to ¥1000 on Saturdays, Sundays and holidays. In general, tolls for usage of the Aqua-Line in either direction are collected at the mainline toll plaza on the Kisarazu end.

Toll table of Tokyo-bay Aqua Line
(Kawasaki-Ukishima Junction – Kisarazu-Kaneda Interchange)
Type of car Toll ETC Aqua-Line
Special discount
ETC Pilot Test discount
(from July 2009)
Normal cars 3,140JPY 2,320JPY 800JPY
Midsize cars 3,770JPY 2,780JPY 960JPY
Large cars 5,190JPY 3,830JPY 1,320JPY
Specific large cars 8,640JPY 6,380JPY 2,200JPY
Kei-cars and motorcycles 2,510JPY 1,860JPY 640JPY

See also



  1. ^ "Developments of transportation and industries, do bring a more comfortable life to every body". Tokyo wan Aqua-line. 1998. Archived from the original on 3 December 1998. Retrieved 6 March 2015.
  2. ^ a b c d Shioi, Y.; Nakamura, S. (1994). "8: Design Concept of the Trans-Tokyo Bay Bridge". In Pritchard, B.P. (ed.). Continuous and Integral Bridges. London: E & FN Spon. pp. 75–84. ISBN 0-419-19030-9. Retrieved 8 March 2015.
  3. ^ Nagai, Masatsugu; Okui, Yoshiaki; Kawai, Yutaka; Yamamoto, Masaaki; Saito, Kimio (2014). "23: Bridge Engineering in Japan". In Chen, Wai-Fah; Duan, Lian (eds.). Handbook of International Bridge Engineering. Boca Raton: CRC Press. p. 1048. ISBN 978-1-4398-1030-9. Retrieved 6 March 2015.
  4. ^ "Steel Bridges: Structures in Japan". Yokogawa Bridge Corporation. Archived from the original on 7 January 2015. Retrieved 6 March 2015.
  5. ^ "Girder bridges". JFE Engineering Corporation. Retrieved 6 March 2015.
  6. ^ "Taisei Corporation's Journey over 140 Years" (PDF). Taisei Corporation. 2014. Archived from the original (PDF) on 2 April 2015. Retrieved 8 March 2015.
  7. ^ Funasaki, Tsuneyoshi; Yamada, Norio; Izumi, Yasutaka; Miki, Keizou (1998). "Construction of Trans-Tokyo Bay Highway". IABSE Reports. 78: 43–48. doi:10.5169/seals-59019.
  8. ^ Katakana-shingo-jiten, Gakken 2003, ISBN 4-05-301351-8
  9. ^ Hotta, Kenji (2002). "4: Tokyo Bay Reformation". In Chen, Jiyu; Eisma, Doeke; Hotta, Kenji; Walker, H. Jesse (eds.). Engineered Coasts. Dordrecht: Kluwer Academic. pp. 94–95. ISBN 1-4020-0521-0. Retrieved 6 March 2015.
  10. ^ "JAPAN Big New Crossings Can Use Much More Traffic | TOLLROADSnews". Archived from the original on 2010-02-11. Retrieved 2009-11-02.
The Aqua-Line from above, 2015