The untold story of the daring cave divers who saved the Thai soccer team

Last summer, a few days after a boys soccer team went missing in Thailand's fourth longest cave system, mobile phones began lighting up around the world like modern-day Bat Signals. One belonged to a former fireman from Coventry, England. Another to an IT consultant 80 miles away in Bristol. There was a retired veterinarian from Perth, Australia, and an anaesthesiologist from Adelaide. They were your average middle-aged professionals, largely from Britain, who had one very unique skill set in common—they were among the best cave divers in the world.

The phone calls were short and to the point, no time for long debriefings. The Tham Luang cave was flooding fast, and soon the monsoon would begin, sealing the 12 boys, aged 11 to 17, and their coach in a watery tomb. The cave divers dropped everything and flew to the Chiang Rai province in northern Thailand to help, joining an international team of technical divers from Thailand, military and rescue divers from the U.S., Australia, and China, and the formidable Thai Navy Seals who were in charge of the search in the midst of a glaring global media spotlight.

"There are probably a few hundred cave divers in the world, but only a very few at that level," says Richard Harris, the Adelaide anaesthesiologist (and a National Geographic grantee), who played a pivotal role in the rescue. "The guys on the British team, they are the first guys you call.

The situation at Tham Luang, however, was grim. The Thai Navy Seals, along with a group of European expat technical divers who ran dive shops among Thailand's lush coastal islands were struggling to push past a large cavern that was the at end of the typical tourist route about a half mile inside the cave. One of the boys had mentioned a popular cavern called Pattaya Beach before he disappeared, but that was another half mile deeper inside, and the divers were thwarted by a torrent of muddy water pouring in from that direction. Ben Reymenants, a Belgian expat diver from Phuket, was an early volunteer, and told a reporter it was like "dropping to the bottom of the Colorado River and hand over hand fighting your way upstream."

Because of the extreme lethality of the sport, cave diving rescuers tend to be the undertakers of the caving community, far more accustomed to retrieving dead bodies—at times their friends—than rescuing live ones. British diver John Volanthan, the IT consultant, believed Tham Luang would be no different. He and his diving partner, ex-fireman Richard Stanton, arrived the Wednesday after the boys went missing on Saturday, and slowly, steadily began pulling themselves upstream, fixing heavy climbing rope along the route for others to follow. For the next four days the international divers and the Seals worked 12 to 14 hours in the cave inching their way forward a metre at a time in total darkness, surfacing in each cavern to check for the boys.

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Ten days later, the children had still not been found. Some of the rescuers calculated their chance of survival at 10 percent at best. Volanthan and Stanton were determined to go as far as they could that day, using their air supply sparingly. They reached Pattaya Beach. No boys. The kept going, digging into their reserve air supply, and shutting off their tanks when they surfaced to make it last as long as possible. Finally, in the ninth cavern, more than one and a half miles from the entrance, they removed their masks and were assaulted by a foul odor.

"We thought it was decomposing bodies," Volanthan said, until their flickering flashlights revealed the boys gaunt but smiling faces—immortalized in a helmet cam video that soon went viral around the world. You can hear Stanton counting in the background and Volanthan's calm voice saying, "How many are you? 13? Brilliant!"

Seven Thai Navy Seals, including a doctor, struggled to reach the kids the next day with food and medical supplies and began trying to strengthen them for what came next. The doctor and three Seals had run out of air on the way in and would stay with the boys until the end. But what came next was the dilemma. The boys would have to pass through at least a half mile of passages that were completely flooded to the ceiling. One plan was to stock the boys with food to last for six months until the water subsided. That was ruled out when divers measured oxygen levels in the cave and found they'd already fallen to 15 percent from the normal 21 percent in the atmosphere. They wouldn't survive a month. One plan involved drilling a tunnel into the cavern similar to the one that saved the Chilean miners in 2010. But it was deemed too complicated and too dangerous. Teams of volunteer rock climbers, even the famed bird-nest collectors of Libong Island, had scoured the mountain's deep sinkholes looking for an alternative route to the boys. They found nothing.

The only path left was to dive the boys and their coach out. But none of them had diving experience. Even the Thai Navy Seals who managed to make it back from the boy's cavern felt diving them out of the tunnel with all its twists and turns, vertical passages and snags was impossible. Some of the sumps were more than 50 feet deep. The narrowest pinch point only less than two feet wide. In a tragic emphasis of the point, a former Thai Navy Seal named Saman Gunan, an experienced diver, died while shuttling air tanks into the cave. No one knows how or why, but it put the risk to the half-starved boys in stark relief. In the end the British team decided there was only one option: sedate the boys to unconsciousness, put them in sealed full face masks, and then bind their arms behind them with zip ties, so if they did wake up and panic en route they wouldn't kill themselves or their rescuers. The divers built special harnesses for the boys with handles on their backs so they could swim them out like human duffle bags.

"We were faced with an impossible decision," says Volanthan. "Stay where they were and they are all going to die. If we brought them out, there was a chance some might survive. It was the Devil and the deep blue sea. At the end of the day, the ends justified the means."

Harris was called in for both his cave diving expertise and his medical skills, being only one of only two known cave-diving anaesthesiologists in the world. At first he was totally opposed to the plan. "I didn't think it would work at all," Harris says. "I expected the first two kids to drown and then we'd have to do something different. I put their odds of survival at zero."

And yet, work it did. Slowly and methodically, one by one, each boy donned a wetsuit, was given a Xanex, then injected with ketamine, a heavy sedative that has the added benefit of scrambling memories. Many had to be re-sedated by the divers once or twice en route. While many around the world were aghast when they found out the details, the boys were surprisingly okay with it. And who could blame them? It was if they had fallen down a well filled with primordial human horrors from total darkness to asphyxiation, drowning to hypothermia, starvation to being buried alive. They were cold, hungry, and ready to see their families again. And they were incredibly brave. Not a tear was seen among them.

The boys were in the ninth cavern. Only the experienced cave divers—all volunteers from the UK—would transport the boys between caverns nine and three, helped along at each cavern by the European team—the skilled expat technical dive instructors from the resorts in South Thailand. At cavern three the boys would be given a medical check by the U.S. military team and passed along to a hundred or so rescuers from a half dozen nations who gently passed them along on a rescue sled. One by one out they came, and were quickly evacuated to a hospital in Chiang Rai, where they were found to be in good health. None remembered a thing of the terrifying trip.

The three-day rescue was not without difficulties. John Volantan swam three kids out, and the last one got tangled in telephone wires that had been laid down before the cave flooded. He had to cut the unconscious boy loose before they could proceed. Danish ex-pat Ivan Karadzcic, one of the support divers, lost the guide line when his borrowed caving helmet began to choke him and he couldn't unlatch the strap. Luckily he found the guideline in the total blackness and was able to move on. Chris Jewell, one of the British divers, wasn't so lucky. He dropped the guide line while shifting his human package from one hand to the other and couldn't find it. He ended up feeling a cable at the bottom and following it back into the cavern from which he'd come. Harris was following him out and saw him there, the blood drained from his face. He took the child the rest of the way out.

When it was all over, and the media trucks were gone, many of the divers were given medals for valor from their countries. But they were quick to demur any heroism and heaped praise on the boys and the entire volunteer army that turned out to save them. Karadich, the former Danish insurance salesman turned technical dive instructor in Koa Tao, says he'd heard there were more than 7,000 volunteers on the mountain. Some cooked the 20,000 meals a day provided free to the rescue teams. Some ran the pumps or diverted the streams at the top of the cave to keep the water at bay, buying the boys precious time. Engineers, hydrologists, and drilling teams pounded the rocks to pump out groundwater, flooding the rice fields of hundreds of poor Thai rice farmers who lost their crop and asked for no compensation. Taxi drivers shuttled volunteers back and forth from the airport for free. Others did laundry for the rescue teams. It was a truly international and community effort.

"I've received thousands of messages from around the globe, thanking us for not just saving the kids, but for getting the world together and setting an example for mankind," says Karadzic. "Even if you've never been in a cave before, it was something everyone in the world could relate to. Who hasn't been a kid once, scared to death of the dark?"

For most, just reading about cave diving makes one hyperventilate. Why anyone would choose to do it for fun remains a bit baffling.

"It's a very cerebral sport," says Dr. Richard Harris. "There's no adrenaline rush. It's very much a meditative state of mind. The whole idea is to be very relaxed, calm and smooth in the water. A lot of cave divers are fairly introverted, often quiet. But you couldn't find a more competent, pragmatic, and courageous group of guys that were at the pointy end of this rescue."

After receiving one of Australia's highest awards for civilian bravery, Harrison's fellow rescuer Chris Challen might have been speaking for all cave divers when he told reporters, "We're just a couple of ordinary blokes with an unusual hobby."

Editor's Note: National Geographic Documentary Films has announced plans to produce a documentary film about the rescue, with a tentative release date in 2020. 

We are celebrating the six 2019 Adventurers of the Year, people who pushed adventure further to redefine what's possible. Read about them here.