Man Swims Nonstop Across Ocean for Over 2 Days to Break World Record

A man has broken the world record for the longest non-stop, unassisted ocean swim—traversing a distance of over 80 miles.

Belgian ultra-athlete and adventurer Matthieu Bonne, 29, swum for 60 hours, 55 minutes and 43 seconds in the Gulf of Corinth, Greece, to break the record.

"The only way to know something is real is to go there," Bonne told Newsweek.

The Gulf of Corinth is a stretch of water that extends deep into mainland Greece, separating the southern Peloponnese region from the more northerly parts of the country. It is a semi-enclosed inlet of the Ionian Sea, which itself forms part of the wider Mediterranean Sea.

By Saturday evening, Bonne had covered a distance of 81.4 miles—beating the previous record, held by former Maltese Olympic swimmer Neil Agius.

In June 2021, Agius swam 78.1 miles in 52 hours and 10 minutes between Italy and Malta—a small island nation in the central Mediterranean—according to the Marathon Swimmers Federation (MSF). The organization sets standards and guidelines for endurance swims such as these.

The MSF recognizes several world records for endurance feats in open-water swimming.

The record that has just been broken by Bonne is that for "longest, continuous, unassisted" swim across an ocean.

For this record, the athlete cannot gain a net benefit from surface currents and the swim must be fully continuous—meaning they never exit the water. The swimmer must also avoid physical contact with escort vessels, support personnel, or other objects, be they fixed or floating.

The swim must be conducted without any artificial assistance that will aid performance. Only the designated standard equipment can be used.

Any use of non-standard, performance-enhancing equipment, supportive contact with the swimmer, or "other violation of the spirit of unassisted marathon swimming" is considered an assisted swim.

The allowed, standard equipment includes a swimsuit (no wetsuits); a bathing cap made of latex or silicone; goggles, earplugs and nose clips; sunscreen and grease; safety lights for night visibility; a simple timekeeping device; an escort boat, pilot and crew; and nutrition and water.

"Primary objective is to swim 127 kilometers and get the world record. But maybe I can go beyond that distance, if Poseidon is in a good mood..." Bonne wrote on his website prior to the record attempt.

"The difficulty of this challenge will be extremely high. Perhaps the biggest obstacle to overcome will be the sleep deprivation. Staying awake for that many hours including two or three consecutive nights will be extremely challenging."

To make the swim official, Bonne was accompanied by three observers to ensure that the rules outlined by the MSF were followed.

Bonne began his world record attempt on Thursday—a day later than planned due to strong winds and excessive waves. He was followed by a support crew.

The swimmer faced a number of challenges during his incredible feat, one of which was that the water was colder than expected.

"I was cold for a long time," Bonne said, according to the Greek Reporter news organization.

Aside from the cold taking its toll, the endurance athlete also experienced a number of other problems during the marathon swim due to being submerged in saltwater for so long.

"My mouth gave me big problems. The salt in the seawater made my lips and tongue completely swollen. At one point I wanted to stop because the pain was so unbearable. And then I had to go on for another twenty hours. No idea how, but I kept going," Bonne said.

Due to the lack of sleep, Bonne also suffered from hallucinations. But after more than 80 miles of essentially non-stop swimming, Bonne crawled out of the Gulf late on Saturday evening to complete his record-breaking achievement.

"I can't believe I did. The last three days have been crazy, and now I have a new world record. I'm super happy," he said.

Bonne has previously completed other remarkable feats of endurance. In March, this year, for example, the Belgian broke another world record by cycling 2,249.18 miles over seven days across Arizona.

"Taking on extremely difficult challenges and attempting the impossible still gives me the biggest thrill in life," Bonne said in an Instagram post about a week before his latest swimming challenge. "I thrive on that. To me it's like an out-of-body experience and it becomes very, very addictive!"

Earlier this year, French open water swimmer Stève Stievenart—nicknamed "Stève the Seal"—completed three crossings between the California coast and Catalina Island, swimming for more than 51 hours nonstop. The feat had never been achieved before.

The three-way crossing involved swimming from Catalina to the mainland, returning to the island, and then going back to the mainland again. The island lies just over 20 miles offshore from the coast of Long Beach in Los Angeles County.

Stievenart had already completed a "one-way" crossing between Catalina and the Southern California mainland in January 2022.

And in June of that year, he completed a "two-way" crossing, swimming from the mainland to the island and back again—a feat that took the Frenchman more than 28 hours.

Update 09/13/23, 12:15 p.m. ET: This article was updated with additional comments from Matthieu Bonne.