Charles Sturt University (CSU) student Mr Lachlan Hinds has become an exclusive member of the Triple Crown of Open Water Swimming.

The 18 year old is believed to be the youngest member of the Triple Crown after he swam across the Catalina Channel off Los Angeles in the USA earlier this month, finishing the 20.2 miles (32.5 kilometres) in nine hours and 31 minutes.

Mr Hinds, from Sydney, is a first year Bachelor of Medical Science Radiation student in the School of Dentistry and Health Sciences at CSU in Wagga Wagga.

Members of the Triple Crown of Open Water Swimming successfully complete three marathon swims: the English Channel; the Catalina Channel between Santa Catalina Island and the Southern California mainland; and around Manhattan Island.

Mr Hinds swam in the dark for most of his nine and a half hours in the Catalina Channel.

"The swim begins at midnight and because it was pitch black it was impossible to distinguish the horizon so one of the main challenges I faced was coping with the extreme sea sickness and vomiting every 15 minutes," said Mr Hinds.

"I knew that I could swim for at least eight hours under those conditions and that the sun was coming up and it was a matter of having a strong mental state to pull through."

The swell was three metres, the water was choppy and cool, and the marathon swimmer was bitten by small stingers.

He was accompanied by Mr Michael Renford – a Triple Crown holder and son of famous long-distance Australian swimmer Mr Des Renford, MBE - and paddler Mr Anthony Johnson on an Australian surf rescue board.

Four days after his successful crossing, Mr Hinds completed the Ederle Swim, a 17.5 mile swim from Manhattan to Sandy Hook in New Jersey. He finished first in four hours and 51 minutes. 

As a 16 year-old in 2012, Mr Hinds swam the English Channel, and as a 17 year-old he completed the Manhattan Island marathon.

Mr Hinds is a Bondi Surf Life Saver when in Sydney and a swimming coach in Wagga Wagga.

He manages to juggle a strict training regime with university study and said swimming keeps his mind focused.

"I've grown up with swimming, it's something I enjoy and I find it clears my mind so I'm alert for university classes. My lecturers at Charles Sturt University have been very supportive and it's allowed me the flexibility to combine study with my swimming," he said.

"Completing the triple crown has been a goal for the last three years and I'm not sure what's next. There's a lot of water in the world left to swim."