Applying treatments at Dragonhill Spa in Seoul. Chang W. Lee/The New York Times

My friend Arcadia Kim has three children and a Harvard business degree, but when she tried to negotiate on our behalf with the lady in charge of exfoliation at the Dragonhill Spa in Seoul, she did not stand a chance.

We were standing in the heart of the jimjilbang, or Korean bathhouse, in a steaming, all-female bathing room where scrubs are administered (as they are across the land) by strict middle-aged women, more than a few of them with potbellies, who wear nothing but sexy black lace bras and underwear. Arcadia had whispered to me that the women were ajummas, which means “aunties” and connotes matronly, working-class women known for no-nonsense warmth and authority.

Our ajumma insisted we needed full-body scrubdowns. We only had so much time, Arcadia protested. The woman shook her head, unyielding. A moment later, we were lying on the slippery plastic tables, being subjected to what felt less like a spa treatment than some sort of primal tough-love routine. Our ajummas scoured us with rough yellow washcloths, walked on top of us, pummeled and slapped us, the popping noises bouncing off the wet tiles. At one point my ajumma shook me to open my eyes and pointed with apparent pride to gray lumps, bigger than rice grains, clinging to my arms. I wondered if they were one of the cutting-edge Korean skin care products I had heard so much about. No, they were clusters of my own dead skin cells. She finished by covering me in hot towels, leaving me feeling like a baby: I was completely and passively in the care of an older woman, my skin was soft and new, and I was surrounded by a world I was only beginning to understand.

Inside the Dragonhill Spa sauna. Chang W. Lee/The New York Times

Most American spas are cocoons, intended to seal off the outside world, and many travel spa experiences offer only tenuous, forced connections to the local culture. (Just how Mexican is the $263 Mayan Sanctuary Ritual massage at the Ritz-Carlton in Cancún?) But as I discovered during a trip late last year, spas, bathhouses, saunas and cosmetics stores can be some of the best places to truly see South Korea, a country that is still figuring out how to share itself with foreigners.

If you walk the streets of Seoul, you may see little more than unremarkable gray buildings, as more than a few disappointed American tourists have noted. But if you visit South Korea’s jimjilbangs and epic lip gloss emporiums, you will see the country far more deeply: its culture of ceaseless self-improvement and corresponding quest for relaxation; its ingenuity and love of the new, twinned with stubborn conformity and oppressively narrow standards; the commercial instincts that have made Seoul the center of Asian pop culture and propelled brands like Samsung and LG around the world; and gender and family dynamics that can seem traditional except when they’re not (couples go for skin care appointments together, and if you want entertaining visual evidence of how seriously some men attend to their appearance, Google “Korean male perm.”)

Memo to lady travelers: A few days in Seoul will also give you a chance to girl-out on a scale, and at a cost, that most of us never could in the United States. At home, I barely pause over the creams and treatments in women’s magazines: Who has the money or the earnest belief in their supposed magic? But in Korea, I happily gave myself over to the ubiquitous, high-quality, low-cost beauty culture. You can buy hand cream that warms your skin when you apply it, little adhesive heating pads to ease menstrual cramps, “air cushion” compacts that apply foundation in the thinnest possible layers and face masks that contain ingredients from snake venom to ground-up bits of animal placenta. At the start of the trip, I missed my husband and daughter, but after a few days, I realized I needed my girlfriends from home instead.

Luckily I had Arcadia. As the ajummas released us, one offered us a swig from her own thermos of iced coffee; somehow we had earned her approval. We declined the coffee but bought slow-baked eggs, a traditional jimjilbang snack, and Arcadia produced two of the foil-sealed face masks Korean women are crazy about.

A woman from China tries out some makeup at Etude House in Seoul. Chang W. Lee/The New York Times

We had not seen each other since we graduated from the same exurban New Jersey high school, and we lay in our spa-issued cotton uniforms, toggling between gossip about our old classmates and Arcadia’s explanation of Korean spa and beauty practices. The details she provided from her own life were intriguing. Her 4-year-old daughter and some of her friends had perms. When her family took a portrait together, the photographer had used Photoshop to slim Arcadia’s arms without asking first. For a few weeks after her third child was born, she had checked into one of Seoul’s newly popular postnatal spa-hotels, which offers daily massages, lactation help, 24-hour infant care and luxurious, quiet rooms.

But Arcadia, the most confident person I knew in high school, had never been to a jimjilbang before, in part because even she had been intimidated by the prospect of silent judgment. “This is where mothers take their daughters-in-law to check out the marital packages,” she said, only half-joking.

Last year on a family trip to Japan, my husband, daughter and I visited Hoshinoya Karuizawa, a resort in the mountains northwest of Tokyo that turns bathing into an experience of minimalist splendor. We soaked for hours each day, moving silently through pools devoted to meditation, immersing ourselves in wooden baths filled with kumquats, and watching Japanese families relax in outdoor pools that mimicked mountain streams. The Hoshino chain, with its contemporary versions of traditional Japanese ryokans, or inns, is an example of Japan’s genius for preserving its culture while marketing it to outsiders — a skill that Korea, for all of its energy and success, still largely lacks. In Tokyo, we also visited more modest bathhouses, neighborhood joints with vending machines and large-screen TVs in the lobbies. But even those places carried a glow of cleanliness and serenity: the bath as Shinto-Buddhist ritual.

Korean jimjilbangs are their cousins, newer versions of the public bathhouses that became popular during Japanese rule, and some of the facilities look the same in the two countries, down to the little stations where you rinse yourself before immersing in hot medicinal pools. But going to a jimjilbang in South Korea can be like having a shvitz and a bath at a mall — in some cases, a mall that is on a cruise ship. The most elaborate jimjilbangs are multistory, self-contained universes with magic shows, Korean barbecue restaurants and corporate team retreats. (According to one Korean expression, you’re not really friends with someone until you’ve bathed together naked in a jimjilbang.) A popular TV variety show even has a regular segment set in a jimjilbang called, “Don’t Laugh in the Sauna.” The host asks celebrity guests nosy questions in a funny accent, and if they laugh, they are doused with water.

Spa Land in Shinsegae department store in Busan, South Korea. Chang W. Lee/The New York Times

Based on my visits to bathhouses in three cities — just a few of the thousands of facilities spread across the country — this is what you’ll find: admission to a jimjilbang is almost always cheap, less than $10 for a locker, as much soaking and sauna-going as you can manage, and a cotton uniform that imposes Confucian conformity, in some cases making everyone look like a character on “Orange Is the New Black.” Little is in English, so wandering around is bewildering fun: You are likely to see saunas inspired by Egyptian pyramids; little heating coils, the kind you see in toasters, built into the floor; and salt rock rooms said to draw toxins out of the body. The facilities are generally clean but rarely posh, and often filled with passed-out bodies — living, snoring symbols of a country so overworked that it switched from a six- to a five-day workweek only a decade ago. Couples intertwine on the heated floors, seeking the kind of privacy in public space that they can’t have at home, where living spaces are small and many young people live with their parents longer than in the United States.

Jimjilbangs around the country vary in their exact amenities: Dragonhill Spa in Seoul, where Arcadia and I were scrubbed, is kitschy and a little dingy but popular, especially with those who pass out there overnight after an evening of heavy drinking. In Busan, South Korea’s second-largest city, the Shinsegae department store has a far sleeker jimjilbang, with gleaming wood surfaces and a “wave dream” room that simulates the feeling of being in deep water. Near Suncheon, also in the south, I visited a jimjilbang in a bamboo forest with a “groundhog sauna” that gently warms your body while leaving your head exposed to the winter sunshine and mountain mist.

One morning in Daejeon, an unremarkable-looking city in the center of the country, I ducked into a drab office building housing a jimjilbang that seemed like a hidden water world. Before entering the baths, you’re supposed to shower, but not in the American sense. A Korean shower is a top-to-bottom exercise involving cascades of suds, dental floss and sustained scrubbing. Several women in their 20s and 30s were gently washing their mothers, vigorously but with a tenderness that conveyed generational respect. I moved from one pool to another, glancing back at them: 20 minutes later, they were still scrubbing, the older women’s skin now bright pink. As I dried off and left, the daughters were still at work. The place wasn’t anything special, which is why it seemed so special indeed.

Ask a young Korean woman what beauty routine she follows and she will probably tell you that she is a bad person to ask, that she doesn’t buy into the national quest for self-beautification. O.K., she sometimes goes for a treatment in which her face is kneaded and pinched, supposedly making it tighter and slimmer. She gets her eyeliner tattooed on every few months, she will admit. To lose weight and tighten up, she buys 10-packs of sessions in which her lower body is pummeled in ways that are supposed to make it firmer. She uses BB cream (a supercharged tinted moisturizer), three kinds of cleanser on her skin and another moisturizer made with snail mucus for its healing and anti-aging properties. Her scalp dries out in winter, so she goes for treatments with aestheticians who track its moisture level with magnified images, like X-rays at the dentist. But really, she will tell you, that’s nothing compared with what her girlfriends do.

Spa Land in Busan. Chang W. Lee/The New York Times

In the American ideal, beauty is supposed to look effortless, a sun-kissed woman without a hint of makeup glowing on a California beach. But in Korea, like so much else in a country that lifted itself from poverty to prosperity in a few exhausting decades, beauty is associated with hard work. When the beauty magnate Helena Rubenstein decreed that “there are no ugly women, only lazy ones,” she could have been peddling stem-cell cream at one of Korea’s massive department stores. One morning in Seoul, I showed up for a manicure at a nail place in Gangnam, the flush neighborhood made famous by the Psy song, lined with luxury cars and ritzy salons. The proprietor took one look at my nails, which were nowhere near a personal low, and gasped in apparent horror.

Before my trip, I had heard about the sheer fun of shopping in Korea, and once I started browsing the beauty stores, I understood what everyone had meant. The beautifully packaged products could keep you busy for weeks fixing problems you never knew you had: “shiny foot super peeling liquid” for dry patches, face masks in flavors from chestnut shell to charcoal, milk packs, mung packs, nose packs and body-firming patches in flavors like “mountain zone.” I bought a liquid eyeliner brush for $3.50 that worked better than the ones that cost four times as much at home and cunning little razors that trim eyebrows with less pain than tweezing.

My favorite store was Etude House, a pink fever dream filled with inventive products in playful packaging, geared to teenagers and 20-somethings but owned by the Korean beauty powerhouse Amore Pacific. The idea at Etude House is that makeup is a form of play, and so every store is designed to look like a life-size doll house, filled with toylike cosmetics: hand cream in dispensers shaped like cute animals and face masks with tongue-in-cheek promises to make you look like a black-and-white film star.

One evening, I dropped into a salon for eyelash extensions, drifting off to sleep as a woman with gentle, precise hands glued lashes on top of my own. The same service was available in New York, but it was far cheaper in Korea, and being there had gotten me into the spirit. I woke up endowed with a gift nature had never given me, amazed at what a little money and time could do.

A sauna at Dragonhill Spa. Chang W. Lee/The New York Times

Since I had only one girlfriend in the entire country, I borrowed two others: Yaeri Song, the founder of the website Seoulist, and Violet Haeun Kim, a freelance writer. Both had spent their lives zigzagging between Korea and the United States, and over dinner in Hongdae, Seoul’s pulsing student neighborhood, we talked about how living in Korea has changed the way they look at themselves and others.

“When I lived in New York, I had one lotion,” Yaeri said, laughing. Now, when she meets New Yorkers in their late 20s, she tends to think at first that they are a decade older. In Seoul, “everyone just looks younger,” she said.

As they talked, I realized tourists have an advantage over Koreans when it comes to their beauty culture: We can enjoy a few adventures and purchases and then fly home, away from the punishing standards that Korean women have to live with. Even though Yaeri is married, she still sometimes flinches at the scrutiny. “Korea is the first place I’ve ever been told by a guy that my pores are really big,” Yaeri said.

I had passed too many plastic surgery clinics to count in Seoul, including some with revealing names (“Second Coming”). Subway entrances are covered in before-and-after ads for the procedures; one shows a wedding ring in the “after” picture. Some women “just get plastic surgery, so they don’t have to deal with the treatments,” Violet said.

Cimer Ocean Spa and Sauna in Busan. Chang W. Lee/The New York Times

Looks are expected to be so homogeneous in Korea that many women’s clothes have no sizes, explained Charlotte Cho, founder of Soko Glam, which sells Korean beauty products to American women. The same silhouettes are expected to fit everyone. Comedians and grade-schoolers get laughs for making fun of anyone who looks different, with darker skin or unusual facial features. There is no cute disheveled look in Seoul: “Korean people want perfection,” Ms. Cho said. Women with small faces are often told that they should be celebrities, because that feature is so prized.

All of this brings up questions for American travelers, likely to raise their eyebrows at the Korean beauty products that offer “whitening” effects, as if that was something that every woman would want or need. I asked my dinner companions a hypothetical question I had posed to others during my trip. My closest Korean-American friend back in Brooklyn is married to my husband’s college roommate, who is African-American. Would my friends feel entirely comfortable in Seoul, with its jokes about anyone who doesn’t conform?

The women chose their words carefully. Korea was becoming less close-minded, they said. But they could not promise that my friends would not be subject to stares, especially outside Seoul; the country was still learning to tolerate and appreciate difference. “I would hesitate to invite a friend who is overweight to visit Korea,” Yaeri said.

On my final day, I reunited with Arcadia for a trip to my favorite jimjilbang of the journey: Spa Lei, a women’s-only facility with pretty robes instead of uniforms and even a little clothing shop, attended by a young woman who was taking selfies every time we passed, utterly lost in the way she looked. Signs offered herbal steam baths for women’s private parts; we stuck to the jet baths. That afternoon, a colleague took me to the Dongdaemun market, where I spent a happy hour and an absurdly small amount of money on Korean costume jewelry, as cheap and appealing as the beauty products.

My backpack was heavy with creams and potions for friends back home, most of them just for laughs. I had already been using the snail cream, which felt like a stickier version of regular face cream, and my skin really did seem softer and less battered by winter. I bought one last ridiculous-sounding product at the airport — a bottle of skin-balancing water — and boarded a Korean Air jet, looking with new eyes at the flight attendants’ neat black buns and pale, dewy faces.