Yet, 20 years on, Lecomte is attempting an even more daunting challenge as he looks to become the first person to swim across the Pacific Ocean, covering 9,100 kilometres.
He will swim approximately eight hours a day.
Lecomte is shaking off any personal threat.
In this picture taken on June 3, 2018, French swimmer Benoit "Ben" Lecomte poses during an interview with AFP in Choshi, Chiba prefecture. I remember times when we would go on the beach and walk and never see any plastic.
After successfully completing the Atlantic swim in 1998, Lecomte vowed "never again" to set off on a long-distance sea journey.
"It made me think what [the] future for my kids is going to be like".
"If we are all aware of it then after it is much easier to take action and to change our behaviour because the solution is in our hands".
Scientific teams accompanying Lecomte, including NASA, will collect more than 1,000 water samples and study plastic pollution, mammal migration and the effect of extreme endurance events on the human body.
"In the Atlantic, I swam for five days with a shark following me, its fin circling", shrugged Lecomte, who previously suffered nasty stings when jellyfish got caught in his snorkel.
He said the hardest part was getting back into the chilly water every morning and admitted that he would hit a "wall" after around four to six hours every day.
"I try to disassociate my mind from my body and everything that happens to my body- pain or cold, I try to put aside".
To keep the boredom at bay, and to perhaps stave off thoughts of just how far he still has to go before he passes beneath the Golden Gate Bridge, Mr Lecomte draws up a detailed schedule of what he will think about for each of the eight to 10 hours he will spend in the water during the epic swim.