Move to Antarctica and hang out with seals?

In the case of University of New England first-year law student Tom Pembroke, it will mean testing the limits of his endurance in a record double-crossing attempt of the English Channel.

In a bid to become the first person to complete the 70-kilometre swim in June, when the Channel is at its chilliest, Pembroke has clocked up about 40km a week training in Dumaresq Dam near Armidale.

Depending on the conditions, the experienced long-distance swimmer expects the double crossing to take between 20 to 26 hours.

Pembroke knows the hazards awaiting him well, having swum the channel one-way in 2013 – a 15-hour effort that left him hypothermic and unable to eat for almost two weeks due to throat lacerations from swallowing water.

"There are likely to be schools of jellyfish, water temperatures as low as 13 degrees Celsius, and this is the busiest shipping channel on the planet," he said. "The tankers all empty their waste tanks, so there's a lot of filth in the water, and the swell can make me very sick."

His other swims include crossing the Northern Channel from Northern Ireland to Scotland (34km).

He has used all his swims to raise money for charity, amassing almost $110,000 in support of SIDS and Kids, disabled children in Papua New Guinea, children with cancer, and MS sufferers. 

This double crossing is in honour of Armidale teenager Sara Lynch, who was diagnosed with the blood cancer acute lymphoblastic leukaemia at age 10.

Although he has experienced everything from shark encounters and severe sunburn to jellyfish stings and injury, he says it is nothing compared to the challenges faced by the Lynch family.

"I want this swim to recognise the incredible spirit and bravery of Sara and her family," he said. "Since her diagnosis in 2015 she's had to undergo chemotherapy, and endured 16 operations, 13 lumbar punctures and six bone marrow tests.

“Sara has been lucky to have a loving, supportive family, but they have struggled with the financial, psychological and logistical challenges of her treatment in Sydney.

“This swim is for her and I hope to raise $30,000 to ease some of the pressures on the Lynch family and to raise awareness of the many other heroes that are personally dealing with cancer."

He added: "I have this unusual ability to be able to swim for long periods in cold conditions, and if I can recognise people going through seriously tough times, then that's a great gift.

“When I start to feel pain or get sick I think of them and what they have gone through. I might take on a tough environment for 24 hours, but these people have been struggling for years. Their heroics is my motivation."

The Lynch family will make the trip to England to support Pembroke’s attempt. His coach Charm Frend, brother Michael and cousin Thomas Gurr, as well as Sara's mother Linda, will comprise his support crew.

To support Pembroke’s swim go to: https://www.gofundme.com/sara-lynch-our-hero?lang=en-A