It's not much thicker than a 20 cent coin, but at 2300km long the Tasman Global Access cable is set to ramp up New Zealand's broadband connectivity with the rest of the world.
The Ile de Re ship has docked in Auckland, as it begins the final stages of the cable laying.
It will run from Raglan to Narrabeen beach in Australia.
Vodafone, Spark, and Telstra have invested $100m into the $1b project.
"Because of our geographic location in the world, we need international connectivity," said Vodafone Technology Director Tony Baird.
"This cable is the only cable to have been laid internationally since the year 2000."
Baird said the cable would launch in January with 500 gigabytes per second.
"We could scale it up immediately to 20 terabytes per second. To put that into perspective, that's about two million high definition TVs all accessing the internet at once."
Spark's general manager of Wholesale Lindsay Cowley told 1 News it was necessary for the telcos to work together.
"We compete furiously at a retail level but as I said, these infrastructure projects just wouldn't happen unless the industry bodies could come together," Mr Cowley said.
"The major players who actually have the cash to be able to make these projects happen," he said.