5 facts about Undersea Cables you probably didn't know

8th June 2022

5 facts about Undersea Cables you probably didn't know

Many of us know the purpose of cabling in domestic and commercial buildings, but do you know how most of the world stays connected to each other? We take a look at some of the astonishing facts about the worlds undersea cable system and how it keeps you connected.

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1.     The longest undersea cable

Keeping the majority of the world connected via the internet is a mammoth task across an extremely large span of land, so it is no surprise that undersea cables are incredibly long, but just how long?

The SEA-ME-WE-3 (South-East Asia-Middle East-West Europe) cable is the world’s largest undersea cable, measuring in at a colossal 39,000km. To put this into context, this cable is the equivalent of about one tenth of the distance from the earth to the moon.

This one cable alone is responsible for connecting 33 countries across 4 separate continents, from Cornwall all the way to Perth.


2.     Isolated Antarctica

While undersea cable systems connect most of the world, Antarctica is the exception. Antarctica’s internet connection is provided solely by satellites.

Several factors are responsible for Antarctica not being connected to the internet via these cables, from its sparse population to its severe conditions, it would not be feasible to extend this cabling system to this part of the world.

3.     Older than you think

Even though having nearly all of the world’s internet connection operate entirely underwater may seem like a relatively new concept, the first installation of an undersea cable actually started as a Trans-Atlantic telegraph cable all the way back in 1854.

This cable connected the province of Newfoundland in Canada to Ireland, and the first transmission using this cable occurred in 1858.

4.     There are a lot of cables at the bottom of the ocean

According to Telegeography¹: “As of late 2021, there are approximately 436 submarine cables in service around the world.”.

These cables are around as thick as a garden hose, but the fibre-optic filaments used to transmit data and signals can be as small as the same diameter as a human hair.


5.     Sharks are a bit of a problem

There are many possible factors that can cause disruption to undersea cables, from boat anchors to natural disasters. However, the most common issue has been sharks chewing on the cables.

While these aquatic predators haven’t cause more than minor damage to these vital cables, action has still been taken to help combat the issue, including Google shielding their cables with specially designed shark-proof wire wrappers.


Next time you’re browsing the internet, you may pause and think about how you can watch videos or read the latest news, thanks to a network of undersea cables.

For a range of cables and accessories for slightly smaller projects, you can find out more here.






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