Beyond the Size

Discover the Marvels of the World’s Longest Underwater Tunnels!

Discover the Marvels of the World’s Longest Underwater Tunnels!

The world has always been fascinated with traveling under water safely as a result of the convenience it offers. For as long as we can remember, people have been trying to figure out ways to connect land masses, and one of the most innovative ways to do so is building tunnels underwater.

These tunnels connect human beings to places previously unreachable, opening doors to new experiences and possibilities. In this article, well delve into some of the world’s longest underwater tunnels that have transformed the way we live and travel today.

Seikan Tunnel


Seikan Tunnel is one of the longest and most important tunnels in the world and was built to connect Hokkaido with Honshu’s main island in Japan. The tunnel extends about 53.85 km and operates as a railway transportation center.

The Tsugaru Strait is home to this mammoth structure, which was designed to withstand harsh weather conditions such as typhoons and earthquakes. It took 17 years to complete this project, but it made transportation in Japan manageable for everyone.

Channel Tunnel

One of the most famous underwater tunnels is the

Channel Tunnel, also known as the Eurotunnel, which connects Folkestone in England to Pas-de-Calais in France. This 50-km tunnel, officially opened in 1994, holds the record as the world’s longest undersea tunnel.


Channel Tunnel has helped in the export and import of goods from one country to another, making it a vital component in the transportation of goods in Europe. The tunnel has two main service tunnels, allowing trains to run in either direction.

Tokyo Bay Aqua-Line


Tokyo Bay Aqua-Line is a toll motorway that connects Kisarazu in Chiba and Kawasaki in Kanagawa, Japan. It’s also a breathtaking sight, as it allows motorists to enjoy the stunning view of Tokyo Bay.

The tunnel extends for approximately 14.1 km and consists of a bridge and a tunnel section that goes through the middle of the bay known as the Umihotaru, a man-made island that sits in the middle of the bay. The motorway is also home to the Tower of the Wind, which provides shelter to the tunnel during bad weather.

Bomlafjord Tunnel


Bomlafjord Tunnel is a road tunnel that extends for 7,820 meters under the sea, in Vestland County, Norway. It is a part of the Fyno – Dalshovda – Triangle Link that was built to help connect the neighboring towns.

The tunnel is equipped with the latest technology to keep the underground structure stable and safe for motorists. It is an important link for freight trucks, as it helps transport goods between the towns.

Eiksund Tunnel


Eiksund Tunnel serves as a link between Hareidlandet and Eika islands in Norway. It’s a 7.7-km-long toll ferry tunnel under the North Sea, which took eight years to finish.

The Norwegian Public Roads Administration completed the project in 2008, and it has eased the movement of ferries and other vehicles to and from the islands. The tunnel is used for daily commuting and helps to reduce the overall travel time.

North Cape Tunnel

Located in Honningsvag, Norway, the

North Cape Tunnel is the longest subsea road tunnel in Norway. It extends approximately 6.9 km under the Mageroyfjord and has become a tourist attraction, with hundreds of thousands of visitors flocking to see the magnificent work of art.

King Harald V of Norway inaugurated the tunnel on June 10, 1999. The tunnel provides a convenient and safe way to travel from the mainland to the island.

Severn Tunnel


Severn Tunnel is an essential railway route that connects South Gloucestershire in England to Monmouthshire in Wales. It runs under the River Severn and is approximately 7 km long, taking about 4 years to build.

The Great Western Railway runs through it, connecting major cities such as London and Cardiff. The tunnel is also an important export route, allowing the transportation of goods from one country to another.

Vardo Tunnel


Vardo Tunnel provides a route from Svartnes to Vardoya Island in the Northern region of Norway. It is a 2,153-meter-long tunnel underneath the E75 expressway, which opened in November 2020.

The tunnel is a significant improvement in the infrastructure of the region, making travel on the access road more manageable.

Sydney Harbour Tunnel


Sydney Harbour Tunnel is an important link that connects the Warringah Freeway and Eastern Distributor in Australia. It is a twin-tube road tunnel that stretches for approximately 2.3 km under Sydney Harbour, linking North Sydney and Darlinghurst.

The tunnel was completed in 1992 and is now a vital artery in the road transport network of Sydney. Thousands of vehicles use it every day, reducing traffic congestion in the city.

Thames Tunnel


Thames Tunnel holds the recognition for being the first-ever tunnel to be constructed under a navigable river. It connects Rotherhithe with Wapping in London, England, and extends approximately 396 meters under the River Thames.

The tunnel was designed as a pedestrian tunnel and was officially opened in 1843, attracting thousands of visitors to see the engineering spectacle. Today, the

Thames Tunnel is still in use, providing passage for trains.

The Bottom Line

The world’s longest underwater tunnels are stunning displays of human engineering and ingenuity, providing links to locations that were previously hard to reach or inaccessible. These tunnels are vital components in global transportation systems, connecting countries and continents, and helping to make the world a more accessible place.

As the world continues to develop larger and more complex tunnel projects, people will soon have more opportunities to discover new destinations and experiences. In conclusion, the world’s longest underwater tunnels have transformed the way we travel and connect with each other, providing links that were previously unimaginable.

From the

Seikan Tunnel in Japan to the

Thames Tunnel in London, these tunnels are instrumental in global transportation systems, connecting countries and continents, and making the world a more accessible and connected place. They are a testament to human innovation and engineering prowess, and we can expect even more impressive tunnel projects in the future.

Here are some frequently asked questions to help you understand more about underwater tunnels:

1. How are underwater tunnels constructed?

Underwater tunnels are constructed by digging through the earth or building a submerged tube structure that is then submerged. 2.

How are underwater tunnels maintained? Underwater tunnels are maintained using the latest technology and techniques, such as periodic inspections, cleaning, and repair work.

3. What safety measures are taken in underwater tunnels?

Underwater tunnels are built to withstand various natural disasters such as earthquakes, typhoons and flooding. Regular checks, strict train schedules and emergency protocols are in place.

4. Are underwater tunnels environmentally friendly?

Underwater tunnels can reduce the costs and environmental footprint of travel, with cleaner technologies such as electric train, while reducing travel time and congestion on roads.


When was the first underwater tunnel constructed? The

Thames Tunnel, which opened in 1843, is known as the first underwater tunnel to be constructed beneath a navigable river.

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