The Carnival cruise shiplast Wednesday was near death when he was rescued, according to one of the U.S. Coast Guard officers who saved him.
Aviation survival technician Richard Hoefle told CBS News he believes "the survivor had about 30 seconds to a minute left before we would have lost him."
The 28-year-old man had "an incredible will to survive," Hoefle said.
"He fell off a boat, he didn't have flotation, he didn't have radio or flares," Hoefle said. "He just had to do anything that he could with what he had, which was nothing."
The passenger was reported missing by the crew of the Carnival Valor on Wednesday afternoon, the Coast Guard said last week.
The Coast Guard was then alerted by the crew of a bulk carrier after they spotted the man in the water, and he was rescued Thursday night about 20 miles south of Southwest Pass, Louisiana.
The man, who had been treading water for more than 15 hours, was airlifted to a hospital, where he is recovering from hypothermia.
The Coast Guard shared footage of the rescue on social media.
Asked whether he thinks the man will ever get back out on the water, Hoefle said, "I think he'd go on another cruise. He knows how to survive. He survived once already and, just keep his feet on board this time."