The top 5 longest underwater tunnels in the world

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Join us as we travel down to the top 5 world’s longest underwater tunnels.

Many underwater tunnels have been built around the world, serving as essential connections in regional infrastructure. Let’s uncover the top 5 longest underwater tunnels World and appreciate how they demonstrate human ingenuity.

Entrance to the Seikan Tunnel from the Honshu’s end.
  1. Seikan Tunnel

Seikan Tunnel tops our list of the longest underwater tunnel in word, in terms of overall length, 33.46 miles (53.85 kilometers).

Connecting Japans Honshu and Hokkaido islands the Seikan Tunnel holds the record, as the rail tunnel globally in terms of total length. Its origins trace back to 1954 a period when ferries were the mode of travel between Honshu and Hokkaido.

This extensive tunnel was finished in 1988 stretching a 33.46 miles (53.85 kilometers) and descending to depths of 790 feet (240 meters) beneath sea level. Featuring two stations, Tappi Kaitei on Honshu Island and Yoshioka Kaitei on Hokkaido Island it represents an achievement, in constructing railway stations that serve as vital emergency exits in case of a calamity.

Today, the Seikan Tunnel handles freight trains, solidifying its status as a vital hub for transporting agricultural goods via freight trains.

Read also: T-50: India’s longest transportation tunnel is now open

The Channel Tunnel
The Channel Tunnel
  1. Channel Tunnel

Channel Tunnel is number two in our list of  the top 5 longest underwater tunnels in the world.

The Channel Tunnel, also referred to as the Chunnel spans a distance of 31.35 miles (50.49 kilometers) linking Folkestone, in England to Coquelles, in France beneath the English Channel at the Dover Strait.

In 1986, the UK and France agreed to construct the Channel Tunnel as a rail tunnel of a bridge or a mix of road and rail to join the two countries.

Construction started on both ends of the Dover Strait in 1987–88. Was completed in 1991 officially opening on May 6, 1994. Presently it serves than 10 million passengers over 1.6 million trucks through its rail shuttle service.

The design of the Channel Tunnel includes two single-track rail tunnels and one service tunnel enabling traffic flow, in both directions. Amazing right?

Read also: Which are the top 10 longest road tunnels in the world?

Tokyo Bay Aqua-Line
Tokyo Bay Aqua-Line
  1. Tokyo Bay Aqua-Line

Tokyo Bay Aqua-Line is third in our list with a total length of 14.7 miles (23.7 km)

The Tokyo Bay Aqua-Line seamlessly integrates road and rail infrastructure through a 5.9-mile (9.6-kilometer) tunnel, boasting a total length of 14.7 miles (23.7 km), connecting Kawasaki and Kisarazu across Tokyo Bay in Japan. Since its inauguration on December 18, 1997, travelers have been treated to a distinctive journey thanks to the incorporation of artificial island sections along its route.

Consisting of two 10-kilometer (2.6 miles)-long tunnels, known as the Aqua Tunnel, passing beneath Kawasaki waters, and a 5-kilometer (3.1 miles)-long bridge, the Aqua Bridge, spanning Chiba waters, this expressway showcases innovation at every turn. Additionally, it features two artificial islands, with “Umihotaru” serving as Japan’s premier marine rest area. Strategically positioned, Umihotaru facilitates the transition from tunnels to bridges, enhancing the overall travel experience along the expressway.

Read also: Europe-Africa Rail Tunnel Project to Connect Two Continents

In the image, we see the interior of the Ryfast tunnel located in Stavanger, Norway.
In the image, we see the interior of the Ryfast tunnel located in Stavanger, Norway.
  1. Ryfast Tunnel

Located in Rogaland County, Norway, the Ryfast Tunnel System comprises two tunnels stretching a total of 8.9 miles (14.3 kilometers) beneath the sea is number four in our list of the top 5 longest underwater tunnels in world.

The Ryfast Tunnel system features two dual-lane tunnels: the Solbakk or Ryfylke Tunnel, which links Solbakk to the island of Hundvag in Stavanger, and the Hundvag Tunnel, connecting Hundvag to an underground tunneled highway interchange with the E39 Eiganes Tunnel. As an integral segment of the European Route E39 highway, the Ryfast Tunnel facilitates connectivity between the towns of Strand and Hjelmeland.

The construction of the tunnel system spanned a decade and involved excavating more than 88 million cubic feet (2.5 million cubic meters) of rock. Ryfast Tunnel holds a world record, and which record is that? Ryfast Tunnel holds the record as the world’s deepest subsea road tunnel, reaching a maximum depth of 958 feet (292 meters) below sea level. Opened in 2020, the tunnel system serves as a replacement for the Høgsfjorden ferry crossing.

Read also: Longest railway tunnels in the world

Underwater roundabout in the tunnel.
Eysturoyartunnilin tunnel; underwater roundabout
  1. Eysturoyartunnilin tunnel

Established in the year 2020 the Eysturoyartunnilin, also called the Eysturoy tunnel stretches a distance of 6.9 miles (11.2 kilometers) beneath the North Atlantic Ocean linking the two islands, in the Faroe archipelago, Streymoy, and Eysturoy.

Eysturoyartunnilin tunnel also has a Word record!

Reaching a depth of 613.5 feet (189 meters) below the seabed at its deepest point, this underwater passage comprises a configuration of three tunnels; however, its standout feature is undoubtedly the vibrant center intersection—the world’s first and only subsea roundabout affectionately known as the “jellyfish roundabout.”

The underwater roundabout stands as a marvel of engineering and a delight, for all senses illuminated by enchanting multicolored lights and adorned with a sculpture accompanied by music.

Summary of the top 5 longest underwater tunnels in the world

  1. Seikan Tunnel – Length: 33.46 miles (53.85 kilometers) – Location: Japan
  2. Channel Tunnel – Length: 31.35 miles (50.49 kilometers) – Location: England-France
  3. Tokyo Bay Aqua-Line – 14.7 miles (23.7 km) – Location: Japan
  4. Ryfast Tunnel – Length: 8.9 miles (14.3 kilometers) – Location: Norway
  5. Eysturoyartunnilin – Length: 6.9 miles (11.2 kilometers) – Location: Faroe Islands