A 13-year-old boy recounted on Tuesday how he swam for four hours through choppy waters off Western Australia to get help for his family, a feat rescuers described as “superhuman.”

The boy, identified in local media as Austin Appelbee, swam about four kilometers (2.5 miles) to shore after his mother and two younger siblings were swept out to sea near the tourist town of Quindalup.

The family had gone kayaking and paddle-boarding on Friday afternoon when conditions suddenly worsened. Strong waves flipped their boards and filled their kayak with water, dragging them farther into the open ocean.

“I was really scared,” the teenager told reporters. “I was just thinking in my head, like thinking I was going to make it through. But I was also thinking about all my friends at school, and friends at my Christian youth,” he said.

“I just said: ‘Alright, not today, not today, not today. I have to keep on going’.”

The boy said he initially swam wearing a life jacket but later removed it to move more freely.

“I was very puffed out, but I couldn’t feel how tired I was,” he said.

To stay focused, he said he thought of happy moments and even sang the “Thomas the Tank Engine” theme song while battling the waves.

“At this time, you know, the waves are massive, and I have no lifejacket on. So anyway, I just keep swimming. I do breaststroke. I do freestyle. Survival backstroke.”

When he reached shore, the teen called emergency services and urged them to deploy boats, helicopters and planes.

“My family is out at sea,” he told rescuers.

Marine rescue volunteer Paul Bresland said the boy’s four-hour swim ultimately saved his family, who were later found clinging to a paddleboard in open waters.

“He swam, he reckons, the first two hours with a lifejacket on,” Bresland told national broadcaster ABC. “And the brave fella thought he’s not going to make it with a lifejacket on, so he ditched it, and he swam the next two hours without a lifejacket.

“I thought, mate, that is incredible,” Bresland said, describing the effort as “superhuman.”

Police Inspector James Bradley said the boy’s actions “cannot be praised highly enough.”

“His determination and courage ultimately saved the lives of his mother and siblings,” he told ABC.

The boy’s mother, identified in local media as Joanne, was also praised for keeping her children alive while stranded at sea with her other son, 12-year-old Beau, and eight-year-old daughter Grace.

“It seemed nice and calm to begin with,” she told reporters.

“One of the hardest decisions I’ve ever had to make was to say to Austin: ‘Try and get to shore and get some help, this could get really serious really quickly’,” she said.

“As the sun went down I thought: ‘Something’s gone terribly wrong here’, and my fear was that Austin didn’t make it,” she added. “Everything goes through your head.”