Glyn Marston, aged 58 from Willenhall, is aiming to complete the challenge in 2023 when he will turn 60.
He is training at Cliff Lake in Kingsbury, north Warwickshire.
Mr Marston is a fan of gruelling events and his past achievements include running along the Grand Canyon and a 150-mile non-stop race.
No date has been fixed yet for his latest adventure but Mr Marston is aiming to set off from Birmingham's Bullring, before heading through Europe in Montreux, in Switzerland, which overlooks Lake Geneva.
He estimates the bike ride will take him six days and then he will complete the swimming stage on the seventh day, where he will cover the distance of the English Channel in the water.
Mr Marston is planning to take a small support crew with him, which includes two friends - one a bike mechanic and another a strong swimmer - along with his wife who will cook.
He says he is spurned on to carry out such activities after he was unable to fulfil his dream of serving in the army due to epilepsy.
Mr Marston, who works for the NHS as an asbestos surveyor, said: "I think for most of my adult life, I have tried to prove to myself I was fit enough and tough enough to be the soldier that I was never able to become.
"Even now I am doing things I probably shouldn't at my age, constantly challenging myself with events and sports."
He began doing endurance events in 1993 after he quit smoking, with his preferred sport being running.
However, in 2007, he was no longer able to run after having his right knee replaced due to a motorbike accident.
Since then, he has turned his attention towards cycling and more recently open water swimming, which is why he is aiming to swim around Lake Geneva.
"It is one to tick of the bucket list," he said.
Endurance events nothing new for Glyn
Glyn Marston started taking on endurance events in 1993.
The charity campaigner has completed the length of the UK on a bike, competed in the London Marathon wheelchair race and completed one of Europe’s most gruelling races.
His running career includes the Spartathlon in Greece, which he ran in 2004 and was one of only two Britons to complete the 147-mile course, run in sweltering heat, from Athens to Sparta.
He completed the Rome Marathon in 2006, giving away the medal he won to a child who suffered from a heart condition, and ran from London to Brighton in 1998 to raise funds for Old Hall Special School in Bentley.
He finished second in the Grand Union Canal race between Birmingham and London in 2004 and broke his personal best the next year.
His running career, which saw him run 65 marathons and 46 ultra-distance races, ended in 2007 when he was found to have irreparable damage to his right knee and underwent a complete knee replacement.
Despite this blow, he didn’t give up taking on endurance challenges and has completed several rides from John O’Groats to Land's End on a bike and also cycled from Pisa in Italy to Blackpool two years later.
He became an international sportsman when he was selected to be part of the Wales national dodgeball team at the age of 51 in 2014.
He was chosen to be a torchbearer for the 2012 Olympics and named ambassador of the year in Walsall in 2017.