KAILUA-KONA, Hawaii — Evan Roshak had just settled into his writing class at Portland State University when he noticed a classmate wearing shorts on a frigid winter day and sporting a distinctive red tattoo on his right ankle.

“Are you an Ironman?” Roshak asked his classmate Will Watson.

Yes. In fact, Watson had gotten the tattoo after qualifying for this year’s Ironman World Championship in Hawaii. And since Roshak had Ironman aspirations, too, he began to train with Watson, and ultimately qualified this summer.

The two Oregon students are part of an atypically large contingent of undergraduate students who are here for triathlon’s pinnacle race. From Clemson to Dartmouth, and Loyola Chicago to the University of Utah, at least a dozen men and women from N.C.A.A. schools are taking up to a week off from classes, and juggling midterm exams and papers, to compete in what triathletes simply call Kona.

The surge can be explained, in part, by the coronavirus pandemic, as these athletes, hypercompetitive by nature, embraced long runs, indoor and outdoor bike rides, and endless pool laps to ward off isolation and set new goals.

But more broadly, triathlon is having a moment among young athletes. More than 40 N.C.A.A. schools now offer women’s triathlon as a varsity sport, up from just a handful less than a decade ago, with the newest being the University of Arizona. And with college athletes now free to make money from arrangements that capitalize on their renown (known as name, image and likeness deals), competing in extreme sports like triathlon is more financially realistic.

Small wonder, then, that Ironman, hoping to drum up interest among college sports fans, just announced a 70.3-mile race in State College, Pa., in July 2023, which will end at the 50-yard line of Penn State’s Beaver Stadium.

“The conventional sense is that you don’t do these races when you’re young and your body is still developing, and it’s an old retired dad’s game because they have the time and the financial freedom to do these things,” said Roshak, 22, a senior history major. “But I think there’s a new understanding of what young people can do.”

The Ironman totals 140.6 miles — 2.4 miles of swimming, 112 miles of bicycling and 26.2 miles of running — and must be completed in 17 hours. That is more than double the swim leg, and more than four times the bike and run legs, of the Olympic triathlon.

Kona is actually the second championship to be held in 2022. The 2021 edition of the race, which was postponed by the pandemic, was held in May in St. George, Utah — the first time the championship was staged outside Hawaii. The 2020 race was canceled.

To herald its return to Hawaii, Ironman, which is owned by Advance Publications, invited Chris Nikic, the first person with Down syndrome to complete an Ironman, and Sebastien Bellin, a former Belgian professional basketball player who almost lost his legs during the 2016 Brussels terror attack, among others, to compete.

As for the 82 professional triathletes vying for the $125,000 first-place prize, this year’s race marked the first time the men’s and women’s races were held on separate days since the first Hawaiian Iron Man Triathlon in 1978.

In an upset, Chelsea Sodaro of Mill Valley, Calif., a former All-American runner at the University of California, Berkeley, captured the women’s race on Thursday in 8 hours 33 minutes 46 seconds. Daniela Ryf of Switzerland, the reigning champion, finished eighth, half an hour behind Sodaro.

The men’s race began at dawn Saturday, and the leaders were expected to finish by midafternoon. Kristian Blummenfelt of Norway, the defending champion and Olympic gold medalist, was the prohibitive favorite. One of the sentimental choices, though, was Tim O’Donnell, the 2019 runner-up, who was competing in his first race since he nearly died from a heart attack, midrace, in March 2021.

More than 5,000 people registered for Kona, with nearly half coming from Europe. And while the average competitor’s age was 45, around 100 people — a sizable contingent — came from the youngest age group, 18 to 24.

Since 2011, the number of women ages 18 to 24 registering for Kona has increased by 68 percent, and the number of men by 56 percent.

“There is some magic here,” said Sarah Sawaya, a 19-year-old sophomore at the University of Mississippi, who was the youngest American participant. “I am so glad I got to experience it.”

Most of the American college students had competed in either swimming or cross-country in high school. A few, like Sawaya, have parents or siblings who have done marathons or triathlons.

Two had been accomplished skiers in Oregon (slopestyle) and Utah (big mountain). Another had played high school golf for four years outside of Chicago.

One common thread, though, was a fascination with pushing the limits of endurance, at younger and younger ages, thanks in part to the success of the Norwegians in long-distance running.

“The Norwegians are dominating,” Roshak said. “They’re young, and they’re rewriting the rule book in terms of what your body needs to be.”

Peyton Thompson, 20, the youngest male qualifier, said he marveled at the Norwegians’ obsession with data analysis, science and nutrition.

Thompson had once been a promising point guard in northern Florida, playing on top youth basketball teams. But after sustaining serious knee injuries, he gave up his dream of playing college hoops and enrolled at Duke with pre-med aspirations.

Then the pandemic hit. And although he lived on campus while taking online classes, he was unable to join a slew of clubs, as he had originally hoped. So voilà, triathlon.

“I had to learn how to swim,” said Thompson, a neuroscience major.

Thompson is one of three Ironman students from the Research Triangle. Andrew Buchanan, from Redondo Beach, Calif., is a senior at the University of North Carolina. Corinne Mouw, a native of Pittsgrove, N.J., is a senior at North Carolina State, and active in the school’s triathlon club.

Even though Mouw’s classmates were sent home in March 2020 because of the pandemic, she stayed in Raleigh, working in a co-op job that was part of her mechanical engineering major. But everyone stayed connected through Strava, an online exercise-tracking tool.

“Even though I couldn’t see my friends, I could see them doing their workouts,” she said.

The cost of competing can be prohibitive and easily amount to $15,000 annually, Roshak estimated, for a coach, a bicycle, separate suits for land and water, race registration fees and more. Sponsorships with companies can defray the costs through clothing and equipment discounts, but many triathletes lean on their families and work part-time jobs.

Finances have always loomed large for Frasier Williamson, 24, of Kaysville, Utah, who got a scholarship to run cross-country for Weber State.

Following a two-year Mormon mission to the Philippines, Williamson, now a junior, was training with his college teammates and getting back in shape. But he learned he would not get a scholarship as the athletic department tightened its spending during the pandemic.

“Either I’d have an essentially full-time job to run for college and get another full-time job to pay for college, or I could read the writing on the wall and try something else,” he said.

Jordan Ambrose, 20, almost committed to swim for McKendree University in Illinois as a sprinter. But after she was diagnosed with thoracic outlet syndrome, she stopped swimming and enrolled at the University of Southern Indiana, near her home in Mt. Vernon, Ind.

Itching for activity during the pandemic, she began training for marathons with her cousin. Only when she realized that she could swim long distances without pain did triathlons emerge as an option.

After she finished her first triathlon, Ambrose was contacted by Trine University, in northeastern Indiana, which won the N.C.A.A. Division III triathlon title in 2021. Are you interested in transferring?

Ambrose was intrigued but declined, in part because she wanted to join Southern Indiana’s swim team in its debut season.

“I will now focus on swim,” she said, after finishing the Ironman in 13 hours 12 minutes 9 seconds. “The team, the competitive atmosphere — I love it all.”

Trine is one of 14 N.C.A.A. Division III schools that participate in sprint triathlons in the fall. The races include a 750-meter swim, 20-kilometer bike ride and 5-kilometer run. There are 15 schools in Division II and 12 in Division I that participate, headlined by Arizona State, which has won five straight national titles. More than 300 women from 24 countries are on rosters.

By 2024, triathlon may become an official N.C.A.A. championship sport. And soon, the USA Triathlon Foundation will launch a collective, to be financed by donors, that would pay N.C.A.A. triathletes through name, image and likeness deals to promote the sport on social media, said Tim Yount, chief sport development officer of USA Triathlon.

During Thursday’s Ironman race in hot and muggy conditions, there were moments when Sawaya, the Mississippi student, felt that she could not continue. She wobbled on her bike, buffeted by the Big Island’s fierce crosswinds. Her feet were covered in blisters.

“On the run, I was falling asleep,” added Sawaya, a sophomore studying biomedical engineering.

But she soldiered on, thanking the volunteers donning canary-colored T-shirts who lined the course and befriending other triathletes. As night fell, one man who ran alongside her for 10 miles told her he had a daughter her age.

So when she finished in 15 hours 34 minutes 19 seconds, beaded by a light rain, she raised her arms and beamed. It was 10:19 p.m.

“So many stories,” she said. “All the pain, all the pain — it was worth it.”

She had little time to rest, though, because she had to prepare for an online organic chemistry exam at 9 a.m.