Donnajean Pierson bought two souvenirs in Patagonia a few years ago: a scarf and a field guide.

She also returned from that trip — a nine-day multisport adventure with Wild Women Expeditions — with something that couldn’t be contained in a suitcase: a new friendship with a Yukon woman named Tunde Fulop.

“We connected right away. She might go out and hunt her meat and I’m probably going to go down to the butcher, but we’re both the same type of human beings — we just have different approaches because of where we live,” said Ms. Pierson, 58, a builder and developer.

Since bunking with Ms. Fulop in an EcoCamp Patagonia geodesic dome, Ms. Pierson has traveled from her home in Maryland to the Yukon — twice. The pair convened in Chamonix, France, to train for a Mount Rainier climb — which they also conquered together. They trade regular texts between visits.

Ms. Pierson didn’t go on vacation chiefly to make friends, and she’s not alone: A 2019 Skift Research survey of 1,300 adults in the United States found that only 11 percent consider the idea of meeting new people a top motivator for planning a trip. But if work commitments, family obligations and the demands of everyday life are among the reasons that it’s hard to make new friends as an adult, sometimes it requires traveling — and leaving behind those demands — to stoke new connections and relationships.

“Travel experiences create opportunities that force you to interact with — and cooperate with — strangers. In day-to-day life, we don’t have so many of those moments,” said Jiyin Cao, a Stony Brook University College of Business professor who studies how multicultural experiences influence psychology. “Multicultural experiences provide those experiences; after experiencing them, we tend to become more trusting.”

Like Ms. Pierson, Kelly O’Connor made friends on a group trip. On a Gate 1 Travel tour of Croatia in May 2017, she and her two travel companions “immediately hit it off” with three Ohio sisters. They stayed in touch after leaving the Dalmatian Coast. Two years later, five members of the sextet embarked on another Gate 1 trip to Bulgaria, Romania and Serbia.

“With some people, it’s very superficial. But after sitting next to someone and talking about your kids, your job, being a widow — you know, real stuff — you get to be friends. It was much more than, ‘Oh, yeah, how many times do you go on tours?’” said Ms. O’Connor, a “71 years young” retired special-education teacher who lives in Lewes, Del.

“Whatever kind of travel you’re doing, whether it’s a relaxing, restorative trip or an adventure, having shared, meaningful experiences fast-tracks that sense of closeness, making it much easier to see someone as a friend early on,” said Miriam Kirmayer, a Montreal-based clinical psychologist and friendship expert.

In 2017, Arielle Aquino, of New York City, chatted with a stranger in the lobby of her Los Angeles hotel and ended up eating dinner with him. That evening, Ms. Aquino’s new acquaintance invited her to a New Year’s retreat at Habitas Tulum, a wellness-focused hotel in Mexico.

“For one moment I was unsure, since I really didn’t know this guy. But my intuition told me I could trust him and, I thought, ‘Why not?’” said Ms. Aquino, 29.

Her week at Habitas, which was filled with activities like yoga and meditation, came at a critical juncture: She was bored by her marketing job and trying to figure out what to do next. Finding support in her fellow retreat-goers, Ms. Aquino left Mexico with some 50 additional friends.

“Every member of this group seemed to be at the same crossroads in their lives — despite being from diverse backgrounds, cities and ages — where we were seeking to understand our higher purpose,” said Ms. Aquino, founder of the The Sensualist, a blog and online store focused on sensuality.

After submitting law school applications in 2011, Sam Egendorf also found himself in limbo. So he bought an around-the-world plane ticket that landed him on a diving expedition off the coast of Thailand, where he met a lively, funny couple from Spain.

The trio spent a week hosteling in Khao Lak, a laid-back coastal area north of Phuket. A few months later, when Mr. Egendorf reached Europe, he crashed for two months at the couple’s home, outside Barcelona.

“I can’t imagine another scenario in which we would have become friends, had it not been for those circumstances,” said Mr. Egendorf, now a 32-year-old lawyer who lives in Brooklyn.

“One thing that’s crucial about friendships is that they’re voluntary: We and our friends are choosing to stay connected on an ongoing basis,” Dr. Kirmayer said. “When we leave our trip, the friendship is no longer one of convenience. So we really need to make an effort to stay involved and engaged in each others’ lives.”

Mr. Egendorf flew to Spain for his friends’ wedding, where he gave a speech at the altar. Ms. Aquino’s Habitas friends regularly convene all over the world. And Ms. Pierson and Ms. Fulop are considering venturing back to South America to climb Aconcagua, an Andean peak.

In 2011, Andrew Santelli, a digital production manager at Disney, traded in on a perk occasionally afforded to employees: discounts on Disney cruises. On a two-week sail from Barcelona to Port Canaveral, Fla., Mr. Santelli amassed a dozen new friends. They bonded over daily “five o’clocktails.”

“Cruises present lots of unstructured time where nobody has to be anywhere, so it’s easy to find commonalities,” Mr. Santelli, 37, said.

The “relatively effortless friendships,” as he describes them, continued onshore. One of them, with a woman named Jackie Ryczek, really took off: She and Mr. Santelli are now married.

Sarah Firshein formerly held staff positions at Travel + Leisure and Vox Media, and has also contributed to Condé Nast Traveler, Bloomberg, Eater and other publications. If you need advice about a best-laid travel plan that went awry, send an email to travel@nytimes.com — Sarah is also our Tripped Up columnist.

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