They relied on wind and muscle power for the entire route in a bid to highlight the threat of global warming and the harm done to the environment by carbon emissions.
Beneath a cloudless blue sky, the pair sailed into Sydney Harbour on the Blizzard, a metal-hulled yacht which nearly capsized in the middle of the Southern Ocean two weeks ago when it was hit by a giant wave.
The wall of water smashed the boat on to its side so the mast was forced beneath the surface. The two Britons and the rest of their small crew feared they would be swept overboard.
"That was a bit of a scary moment," Hooper said yesterday.
"Blinding spray was being whipped up by 70-knot winds. A [23-metre] swell came up behind the boat with a huge breaking tip. I could see what was about to happen so I just grabbed a pole and hung on for dear life."
The pair established their expedition credentials in 2006 when they became, at the age of 19, the youngest Westerners to climb Mt Everest.
They then featured in an adidas campaign, Impossible is Nothing, alongside David Beckham.
Just reaching the start of their journey in April last year took eight days. A blizzard meant they could not be dropped by helicopter at the Magnetic North Pole, so they travelled by dog sled led by Inuit guides.
From Greenland they sailed to New York, and from there cycled 18,000km through the United States, Central America and South America to Punta Arenas in the far south of Chile.
One of the toughest stretches was through the Atacama Desert, where for 1600km they saw barely a bird, animal or plant.
With the help of a professional skipper and crew, they sailed the Blizzard, an Australian expedition yacht, to the Falkland Islands and then 15,000km across the Southern Ocean, stopping briefly at the French sub-Antarctic territory of the Kerguelen Islands.
They reached the Magnetic South Pole before pressing on to Hobart, Tasmania, and finally Sydney.
Apart from nearly capsizing, the most sobering part of the journey was seeing the impact of global warming in the Arctic.
"The sea ice has thinned by 50 per cent over the last 20 years," said Hooper, of Wellington, Somerset.
"There are huge changes going on up there which mean we all need to start making changes to our lifestyle to reduce our carbon emissions."
The pair looked forward to a beer and a full night's sleep after snatching only three-hour stretches at sea.
