Ben Mitas sipped Vinho Verde from a stemmed wineglass while he watched his daughter play on a swing one afternoon in January. He had bought the wine from a quiosque, the ubiquitous park kiosks, a luxury of living in Lisbon.

Mr. Mitas and his wife, Megan, moved to Portugal from Florida in 2019, renting a four-bedroom apartment for 2,500 euros (or about $2,700) a month in Campo de Ourique, a quiet neighborhood with small shops and restaurants. Last year, they bought a 19th-century house in Lapa, a historic neighborhood perched high above the river, with embassies and 18th-century palaces and mansions with tiled facades, that they will renovate into their “forever home,” said Ms. Mitas, 31. Mr. Mitas, 40, a mortgage broker, travels back to Florida frequently for work, but their life is in Lisbon where their two small children are in pre-K and day care.

The family fits right in. Here in the Portuguese capital, English speakers are seemingly everywhere. On the day Mr. Mitas took his daughter to the park, two women sat on a nearby bench, strollers at their feet, as they chatted in English.

The previous afternoon, Rita Silva, a researcher at Habita!, a housing rights organization, leaned forward intently on a tattered red sofa, her elbows on her knees, surrounded by bookshelves and hand-painted banners inside the group’s storefront headquarters in the trendy Intendente neighborhood. She was preparing to meet with Lisbon residents facing eviction. Even Habita! is feeling the squeeze: The group’s landlord will not renew its lease, which expires next year. Lisbon “stopped being affordable for the people who live and work in this country,” Ms. Silva said.

Americans, unable to afford the kinds of homes they want in the kinds of domestic cities where they want to live, like San Francisco and New York, are moving to Southern Europe in significant numbers. Drawn to the region by its mild climate and low cost of living, made even more affordable by a strong dollar, many Americans gush about trading a car-dependent lifestyle for the chance to live in a vibrant, European city on the cheap.

What is cheap for these Americans is brutally expensive for southern Europeans, whose average wages are substantially lower than Americans’. Locals are competing for housing against wealthy foreigners in markets already distorted by Airbnbs and corporate real estate investment. The result is a generation failing to launch, with more than 90 percent of southern Europeans under 35 still living at home, rates that eclipse their American counterparts. Those who have apartments face evictions and unpredictable rent increases in cities with weak rental protections, like Lisbon, Barcelona and Athens.

“It’s soul-breaking,” said Alkis Kafetzis, 40, a project coordinator at Eteron Institute for Research and Social Change in Athens, which studies housing inequities.

The surge in foreign investment is no accident. Portugal, Spain and Greece have courted deep-pocketed foreigners and corporations, hoping to attract talent, bolster their economies and spur development. Portugal and Spain recently introduced digital nomad visas that allow remote workers to live in the country for an extended period of time, echoing a similar visa in Greece. In Spain, home sales to Americans jumped by 88 percent from the first half of 2019 to the first half of 2022. Americans were among those willing to spend the most per square meter, bested only by the Danes in how much they paid in the first half of 2022, according to Spanish government data.

By 2022, nearly 10,000 American citizens were living in Portugal, up a stunning 239 percent from 2017, according to data provided by the Portuguese government.

The Americans who are setting roots here are embracing a life where the weather is pleasant, the lunches are long and they can get by with translation apps and a handful of phrases. Americans say that even if they attempt to stumble through a conversation, locals quickly switch to English since the language is so prevalent in European cities. But their children arrive home from school bilingual, giving parents like Mr. and Ms. Mitas access to tiny translators to help them navigate the tricky moments when Google Translate isn’t sufficient.

“Their main concern is lifestyle migration. They really, truly want to live here and have a more cosmopolitan lifestyle,” said Luis Mendes, an urban geographer at the University of Lisbon.

Baptized in the Aegean

“The way you live is so much more free and enjoyable here,” said Christian, 17, as his 8-year-old sister, Evangelia, glided past him on roller skates on her way to take a spin around the dining room table. “Everyone’s calm, it’s not like, ‘do this, do this, do that.’”

The Mallios family is from Colts Neck, N.J., a rural community in central New Jersey with sprawling estates and horse farms, including one owned by Bruce Springsteen.

They arrived in Greece in July 2020, after Melissa and Demetrios Mallios bought a €350,000 house on Evia, an island near Athens. The purchase qualified for a golden visa, a residency program available in several European countries that gives home buyers years of residency in exchange for spending a significant sum in cash on real estate.

The family spent the 2021 school year renting a house in Athens while their children attended an international school there. By 2022, Mr. and Ms. Mallios put their New Jersey home on the market, and bought the €1.45 million condo in Kifissia, a northern Athens suburb with tree-lined streets and multimillion-euro villas hidden behind high stone walls. At almost €427 a square foot, high-end homes sell in Kifissia for about 44 percent more than comparable ones in the rest of Athens, according to RE/Max Europe.

On a Sunday evening, families were strolling around Kifissia’s downtown, which is full of upscale restaurants, cafes and boutiques — Bottega Veneta, Max Mara and Wolford, the Austrian lingerie brand.

The Mallios children now attend a private virtual school, Pearson Online Academy, which allows them to shuttle between their homes in Athens and Evia, but hasn’t given Evangelia many opportunities to learn Greek and make local friends. “I miss New Jersey,” she said.

Her brother, however, has learned the language from his friends on the basketball team. “Throw in a couple ‘malakas’ in your sentence and you sound pretty fluent,” he said, referring to the common vulgarity. And her father, Mr. Mallios, 52, a venture capitalist of Greek descent, speaks the language.

In Athens, home prices were up 13 percent in the third quarter of 2022 compared to the same time a year earlier, according to the Bank of Greece. Americans are increasingly interested in Greece’s golden visa program, with applications up a stunning 740 percent from 2020 to 2021, according to Astons, an investment immigration firm.

Georg Petras, the chief executive of Engel & Völkers in Greece, said Americans flooded the Greek market in 2022, accounting for a quarter of his firm’s foreign transactions. If the trend continues, Americans will become the third largest group of foreign buyers that his company handles.

Tension is painted on the streets of Athens, where graffiti scrawled on the sides of buildings proclaims, “Athens is Not for Sale” and “No Airbnb.”

Greeks earn an average salary well below €20,000 a year in 2021, according to Eurostat, and have been battered by economic turmoil, austerity and inflation. Almost half of Greek renters are struggling to pay the rent, according to a 2022 survey by the Eteron Institute. “Being able to get a breath, to feel a little bit secure about the future is the exception, not the rule,” Mr. Kafetzis of the Eteron Institute said. “This generation is always thinking about the next month.”

At 30, Spiros Stamou owns the taxi he drives, but still lives with his parents, as do his friends. Driving through central Athens, he lamented his lot. “Some people tried to get their own apartment, but ended up going back home,” he said, frustrated that it felt impossible for someone earning €600 a month to afford an apartment that costs €400 a month. “The cost of life, everything is getting higher,” he said.

But for Ms. Mallios, Greece has been transformational.

“When I was back in the States, I felt so out of place,” she said. When friends and family asked her why she chose to leave her home country, she replied: “I went for a beautiful life.”

Last summer, Ms. Mallios, 38, converted to Greek Orthodox at a ceremony at their island house. Wearing a white dress, her blond hair braided atop her head wrapped in a gold-leaf tiara, she was baptized in the Aegean Sea.

On a Lark

The sun was glistening on the Mediterranean Sea as Ryan Ward stood on a bedroom balcony of his house, nestled in the forest above the seaside village of Tossa de Mar, in Spain.

“Where I’m from in California, I could never afford a place like this,” said Mr. Ward, 37, who grew up in Orange County, Calif., where the average sales price is shy of $1 million.

Mr. Ward and his wife, Justyna Ward, bought the two-family home with a pool on the Costa Brava for €515,000 in February 2021. The couple lives with their infant and two-and-a-half-year-old sons in the three-bedroom apartment on the upper level of the duplex. They rent the two-bedroom apartment on Airbnb, and the entire house while they travel during the summer, earning enough rental income to pay the mortgage.

The Wards came to Spain in 2016 on a lark — Mr. Ward’s employer, a marketing firm, offered him a six-month stint in Barcelona that turned into a permanent one. Once they started a family, moving back to the United States didn’t make sense. California was too expensive and Chicago, where Ms. Ward, 36, grew up, was too cold. After living in Europe, they could no longer imagine relinquishing the Mediterranean lifestyle and cultural richness they’d come to cherish in Spain. “What’s the point of moving back?” Ms. Ward said as she sat on her sofa, nursing her newborn son, taking in the breathtaking view of the sea.

Foreigners are plucking up homes along the Spanish Coast, from Costa Brava in the north to Andalusia in the south. Spain’s new digital nomad visa allows remote workers and freelancers to live in the country year round, as long as they earn most of their income outside of Spain and meet other requirements. Pay €500,000 in cash for property, and a foreigner can qualify for a golden visa. From January 2022 to January 2023, the number of parents from the United States looking for schools on the International Schools Database, a website, doubled, with Spain topping the list of destinations.

“If you can make €100,000 a year, you will live very well here,” said Raf Jacobs, the founder of Inspire Property Experts, a real estate consultancy that helps foreigners settle in Spain.

The average Spanish salary was less than €30,000 a year in 2021. In Barcelona, rents have been rising for a decade, reaching an all-time high of €1,077 a month in the fourth quarter of 2022.

“Homeownership society is in crisis in Spain,” said Carme Arcarazo, advocacy coordinator for Sindicat de Llogaters, a Barcelona tenants union.

Globe-trotting newcomers are not to blame for the crisis, said Jaime Palomera, a housing researcher for the Barcelona Urban Research Institute. Investment firms like Goldman Sachs and Blackstone swooped in and bought thousands of distressed properties in the wake of the global financial crisis, turning homes into securitized assets, he said. “This is much bigger than any individual American buying a home here,” he said. “Regardless of your nationality, are you going to buy that home to live in it or you going to buy it as an asset in order to drive up the rent as much as possible?”

‘Life Isn’t Fair’

In Lisbon, the average rent for a two-bedroom apartment, at €1,700 a month in February, was up 39 percent from a year ago, and the average sales price for a two-bedroom was up 10 percent, to €457,730, according to Casafari, a real estate data company.

Between 2020 and 2021, the number of North Americans moving to Portugal doubled, at a time when migration from Europe and South America fell. Private schools have waiting lists and new ones are opening. In 2019, the number of Americans coming to the Carlucci American International School of Lisbon jumped by 60 percent, said Nate Chapman, the school’s director. Now, Americans account for a quarter of his student body, up from 16 percent a decade ago. “Right now is a bit of a gold rush,” he said.

For the Portuguese, with an average salary below €20,000 a year in 2021, the influx of Americans and subsequent rising prices are unsustainable.

Ms. Silva of Habita! said rent protections eliminated in the wake of the global financial crisis left tenants vulnerable to eviction and untenable rent increases. Inside her group’s headquarters, folding chairs were arranged in a circle beneath a yellow tapestry, emblazoned with the phrase, “Casas são para morar” or “houses are for living.” Outside, scaffolding and cranes are as common as the sound of the tourists’ suitcase wheels clattering along the calçada portuguesa, the city’s iconic squared cobblestones.

“We have an explosion of urban reinvestment. It’s all for tourism, it’s all for luxury,” Ms. Silva said.

In response to the mounting housing crisis, Portugal ended its golden visa program in February, part of a sweeping package of changes. Last year, Americans bought more Portuguese golden visas than any other nationality in the world, edging out the Chinese. It was a dramatic reversal for Americans who, just four years earlier, weren’t among the top five buyers of the visa.

Other visa programs for foreigners with means remain intact.

Amelia Guertin has been in the country on and off for the last year, living on a tourist visa while she applies for a long-term one. She arrived in Portugal after living in Hawaii, San Francisco and New York City, cities that felt “wildly unaffordable,” she said. Immediately, she knew she wanted to settle in a place that felt cosmopolitan, but also laid back.

Earlier this year, she hunched over a laptop with her architect, Hannah Reusser, at Rove, a Lisbon bar with plush velvet sofas, exposed ductwork and moody lighting. Ms. Guertin, 31, had already started demolition on a small house she bought last October for €320,000 in Aroeira, a seaside town south of Lisbon, where she can surf.

Ms. Reusser discussed making the three-bedroom, two-bath space more functional, suggesting she rearrange the kitchen and living room. Ms. Guertin, the chief operating officer for a British tech start-up, pushed Ms. Reusser on the deadline. Was June realistic? Ms. Reusser worried it was too ambitious, given pandemic delays and material shortages.

An hour later, Ms. Guertin rushed down cobblestone streets, heading to her Portuguese language lesson a few blocks away, worrying about the schedule. “In Portugal, you have to have a lot of patience,” said Ms. Guertin. “It feels disorganized, but I have confidence that it’s going to get done.”

At Da Noi, a tiny restaurant in central Lisbon, diners squeezed into tables and those who had come for drinks spilled out onto the street, talking in English, German and French. Mixing an Aperol spritz behind the bar was Simāo Martins, 22, an economics student at the University of Lisbon. He works full time, but lives at home with his mother, just like his friends.

“I don’t want to be under her roof forever,” he said. If he got his own apartment, he estimated half of his income would go to rent. So he is contemplating moving to Brazil or the Italian countryside, where the cost of living might be lower. Portugal “is cheap here for you, but not for us,” he told a reporter. “And that bothers me.”

The previous night, about a dozen foreigners and local Portuguese had gathered around a large wooden table at a restaurant for the OneThousandClub, an organization that encourages foreigners and Portuguese to mingle. But the room fell silent when one of the Portuguese guests, Hugo Janes, 44, asked how many would stay if the country were not a tax haven for foreigners.

The vibe turned defensive as the guests, a mix of French, Belgian and Americans, defended their tax status. In the debate, the Americans argued that they pay taxes to the United States.

These policies “are a catastrophe for the Portuguese,” Mr. Janes, a product manager for Vodafone, told a reporter, voicing a growing resentment among his compatriots. “Life isn’t fair, but there needs to be some fairness.”

Bisco Smith, 42, an American graffiti artist who moved from New York to Lisbon with his wife, Jasmine, 39, and their young son, almost a year ago, has mixed feelings about his newfound city.

“There’s a countrywide gentrification happening here. And it doesn’t feel good,” he said, sitting in his 2,000-square-foot artist’s studio near the Beato Creative Hub, an innovation center. “I don’t want to be the American that’s here taking advantage of or displacing people.”

Yet, Lisbon has been a welcoming city after a difficult period in New York, when he and his wife survived two serious car accidents. Since arriving in Lisbon, he joined a father’s group called Expat Dudes and Dads, and his son is learning Portuguese in preschool. “Lisbon means safe harbor,” he said. “My family needed safe harbor and we found it here.”