When I was a teenager, I spent as much time as I could on a surfboard, bobbing on the ocean swell, waiting for the perfect wave. It seldom came.

My surfing years -- summers, actually -- were spent not in San Diego or on Oahu but on Nantucket, where the waves were erratic and generally small. Still, they were waves, sometimes even ridable ones. My first surfboard was an ugly yellow thing with "Easy Rider" airbrushed on the deck and a smashed-in nose patched with spackling compound. I learned in the usual way, by trial and error, rising unsteadily to my knees, then to my feet, wobbling along for a few precarious seconds before the inevitable crash and burn. Eventually I achieved a certain marginal competence. Even on Nantucket, there were big days, when a storm passing to the south would kick up clean, picture-perfect waves that might rise several feet above the head of a standing surfer. I still remember the surge of adrenaline and joy when, largely by accident, I found myself crouched inside the hollow core of one such wave, peering out at the sunlit world through a rotating cylinder of green.

There is nothing that I have experienced, before or since, to match that first essential moment when you plunge down the face of a moving wall of water, that sense of weightlessness and speed. I couldn't get enough of it.

But eventually, of course, I did. As a college student in the San Francisco Bay Area, I occasionally made the trek over the coastal mountains to Santa Cruz, with its powerful Pacific swells and abundance of well-known breaks. But it was never quite the same. The water was cold, the local surfers proprietary and unwelcoming. Then came graduation, responsibility, a succession of jobs in landlocked cities far from the ocean's roar. I still went back to Nantucket. But sometime in my mid-twenties, I caught one last ride, carried my surfboard out of the water and shoved it into the crawl space beneath my parents' house.

There it stayed, dusty and forgotten, for the next 15 years.

With an aplomb his passengers did not share, our pilot guided the small twin-engine Cessna through a series of twists and turns, threading his way through jungle-covered hills that sometimes seemed to pass within feet of our wings. As the wilderness gave way to postage-stamp farms and small cattle ranches, the pilot dropped the nose and aimed toward a small paved airstrip. A cluster of tin-roofed buildings indicated the presence of a village. To my right, the Pacific Ocean glittered in the late-afternoon sun. Then I spotted the waves. From the air, they looked as smooth and evenly spaced as the ripples on a pond.

I had come to Costa Rica to surf. Specifically, I had come to Nosara, an isolated village in Costa Rica's semitropical Guanacaste province, for a week-long stay at a surfing camp operated by Corky Carroll's Surf School of Huntington Beach, Calif. I was accompanied by a friend from Washington, Dave Massey, an attorney who in some respects had even less reason to be there than I did: His knowledge of surfing was limited to the instructional video he had purchased several weeks before we left. But Dave was curious about the sport and liked the idea of a vacation built around vigorous exercise.

Notwithstanding its association with Carroll, a famous surfing champion of the 1960s, the school is run by one Rick Walker, who divides his time between California and Costa Rica. He met us at the end of the runway in a battered Chevy Suburban, like Tattoo on "Fantasy Island." There the resemblance stopped, however. Somewhere in his late forties, Rick was tall, bare-chested and cheerfully profane, with swept-back blond hair and the build of an aging volleyball star. He wore flip-flops and baggy surfer's trunks.

As we soon discovered, Rick's informal style extends to his camp, about 15 minutes out of Nosara on dusty unpaved roads. Its land-based component centers on a simple two-story structure that serves as Rick's house as well as the gathering place for meals and other activities. Students at the school, usually no more than about eight, stay nearby at a small hotel or -- as Dave and I did -- in a compact duplex condominium next to a swimming pool. Just a short walk down "a bitchin' little jungle trail," as Rick put it, is Guiones Beach, an immaculate, four-mile stretch of sand and driftwood bounded by a pair of prominent headlands.

I owed my presence in Costa Rica to my 12-year-old son, Drew. Two summers ago, I had hauled my old board out of retirement and given it to him. Drew took to the sport immediately and, since I now had no board of my own, it seemed only reasonable to buy a new one so I could join him in the water. This I did last summer. Though the waves I caught were few and far between, they were enough to rekindle my interest, and, come fall, I began combing the Internet for surfing camps. Costa Rica was a natural choice. Not only is it an easy trip from Washington, but the country's Pacific Coast boasts some of the shapeliest and most consistent waves this side of Hawaii -- not to mention average water temperatures of around 80 degrees.

Unlike some of the larger and better-known surfing resorts in Costa Rica, Rick's camp emphasizes instruction, which is one of the reasons it had appealed to Dave and me. Still, I had my doubts. I wondered whether it was really possible to teach surfing, which I saw as largely intuitive. I also wondered, given the many years that had passed since I last pursued the sport in any serious way, whether I wasn't setting myself up for a disappointment. Would I really be able to recapture the magic of surfing that I remembered from my youth? Or should I have just stayed home and bought a sports car?

There was some consolation in the knowledge that I was not alone. Notwithstanding its youth-culture image, surfing has in recent years made considerable inroads among the Advil-and-SUV set. This is due in part to the reemergence of the easy-paddling "long board," which has done for wave riding what oversize tennis rackets and golf clubs have done for their respective sports. The growth of the sport among the older and more affluent has helped fuel a boom in surf schools, surf camps and surf travel companies, some of them offering luxury "surfaris" to South Pacific atolls on air-conditioned yachts. There's even a surf shop in downtown Bethesda.

My fellow campers, who ranged in age from 32 to 51, seemed to be fairly typical of surfing's new demographic. Besides Dave, they included Tricia, an adventurous dot-com refugee from Manhattan; Tony, a Wall Street securities trader; Del, a personal-injury lawyer from Huntington Beach; and Quest, a powerfully built Texas businessman and inventor whose white hair and beard made him look like Papa Hemingway. All were new to the sport.

The staff consisted of Rick and two deputies, Kim, a laconic, easygoing Long Islander with sun-bleached blond hair and a skull tattooed on his ankle, and Pio, an ebullient young "Tico" -- as the locals call themselves -- whose English didn't extend much beyond surfing slang. As it happened, they would carry the bulk of the teaching load during our stay. We learned this early on the first morning, when we arrived at Rick's house to find him hobbling around his kitchen on an ankle swollen to roughly the size of an eggplant. Somewhat sheepishly, he explained that he had tumbled off his motorcycle while returning from a local bar the night before. It seemed he would be limiting his role to land-based instruction.

The official program began the first morning at Guiones, a classic beach break where the swells formed languid peaks as they crested on a sandbar perhaps 100 yards from shore. Thinking that I already knew the essentials, I grabbed one of Rick's long boards and headed into the surf while my fellow campers stayed behind to hear his introductory lecture. For the next several days, they would practice in the "white water," the foamy waist-deep zone where the waves slosh in after they have already crested and crumbled -- surfing's equivalent of the bunny slope. Only when the instructors determined that they were ready would they venture "outside," to the deeper water where the waves first take shape.

As it happened, I had trouble just getting outside. Although the head-high waves would not have intimidated a more experienced surfer, they packed a lot more punch than the puny East Coast rollers to which I was accustomed. It was a long, hard struggle through the white water before I finally reached the point where I could straddle my board and catch my breath. After missing my first few attempts, I finally caught a few waves and experienced a taste of the old thrill. My form was anything but graceful, however, and I found I could not remain in the water for longer than an hour or so without taking a rest. The next morning my back and shoulders were so sore I could barely shrug on a shirt.

It seemed this was going to be harder than I thought. Thanks to the variables of wind and tide, we couldn't surf all the time, and it did not take long to fall into a comfortable routine. My day typically began at dawn, when I would wake to the cries of howler monkeys and the rattle of a warm wind in the palms. After breakfast, if the tide was right, I would paddle out for the morning "session," taking advantage of the offshore breeze that blows consistently at that time of day during the winter dry season. (Offshore winds make for the tallest and smoothest waves.)

By mid- or late morning, the wind would usually switch onshore, causing the waves to lose their shape. This provided the perfect excuse for indolence -- napping, lounging by the pool or perhaps reading a paperback in the hammock that hung from the roof of Rick's porch. Sometimes we surrendered ourselves to Deanna, the dreadlocked Austrian masseuse who bicycled up to Rick's house most afternoons to work out the kinks in our muscles at $40 an hour. Later, as the wind died, we would head back out for the afternoon and evening "glass off," when the waves regained their smooth, unruffled shape.

But sport was only part of the experience. During lulls between sets, it was a pleasure just to sit on a board and soak up the view -- the largely deserted beach with its backdrop of tangled vegetation, the foothills with their red-roofed villas, the vast blue ocean with its distant layer of mist. Pelicans swooped into the troughs between waves as frigate birds circled overhead. Other sea birds plummeted beneath the surface and emerged seconds later with gullets full of fish. Once I nearly fell off my surfboard when I glanced to one side and noticed a large pair of eyes regarding me balefully from a distance of about 30 feet. "A seal!" I sputtered to no one in particular. Pio, bobbing nearby, could barely contain his mirth. "No, man," he said. "That's a turtle."

So it was. I watched in amazement as the massive creature paddled lazily in a circle, then sank from view.

The surfing scene was itself a spectacle. Although the waves were far from crowded, they attracted a fair number of local teenagers, who whooped and hollered as they jockeyed for position, cut each other off and generally tried to turn surfing into a contact sport. Some of them could do amazing things on their battered hand-me-down boards. One evening we watched in silent awe as half a dozen or so, silhouetted against a setting sun, caromed off glassy, translucent crests like acrobats in the Cirque du Soleil.

After the last ride of the day, we would gather at Rick's for "bocas," snacks consisting of fried yuca or guacamole and chips, washed down with generous amounts of cold Costa Rican beer. Dinners were simple fare of roast pork or beef or the occasional shrimp dish, invariably accompanied by salad, rice and black beans. For those inclined to night life, there was the Tropicana Disco Bar in Nosara, where the speakers throbbed with techno and salsa and the atmosphere recalled Jimmy Buffett's "Banana Republic," a song about American expatriates in some steamy out-of-the-way beach town:

• Some of them are running ganja
• Some of them are running from the IRS.
• Late at night you will find them
• In the cheap hotels and bars,
• Hustling the senoritas
• While they dance beneath the stars.

Mostly, though, we whiled away the evenings at Rick's, chatting on the porch against a backdrop of jungle noises and the Grateful Dead. I was usually in bed by 10.

After two or three days, I was starting to have more fun in the water. Kim had shown me how to conserve energy while paddling out by using the "turtle dive" -- inverting the board and ducking underwater so that incoming waves would wash over me, rather than sweeping me back toward the beach. He also had noticed that after catching a wave, I often failed to turn as snappily as I should across the face, thus outrunning the wave and causing the board to lose momentum. I corrected the problem and began to get longer and better rides. My companions, too, were making progress. Dave had joined me beyond the breakers, where I watched as he caught his first authentic ride, cruising along the face of a clean, solid "right" -- waves are described by the direction in which they break -- that carried him halfway to the beach.

One day Kim suggested that it might be worth my while to spend the next morning at Ostional, a half-hour's drive up the coast, where the waves broke closer to shore and were reputed to be more powerful than at Guiones.

Rick, hearing of the proposal back at his house, made it sound as if I were in for a thrashing.

"That's a really treacherous wave," he said.

I imagined myself being tenderized against some fearsome submerged reef. "But I thought it had a sandy bottom," I said.

"Yeah, but the bottom's not what's going to get you," Rick said ominously. "That's a thick wave. It's going to eat you alive."

With my confidence thus fortified, we loaded our boards onto the Suburban and left before breakfast, following a rough dirt road that took us past mango groves and elegant stands of teak. After fording several streams -- Ostional is often inaccessible by car during the rainy season -- we pulled up at a tiny cluster of ramshackle wooden buildings, one of them an evangelical church. In front of us was a magnificent beach of black volcanic sand. Tiny tracks marked the path of newly hatched olive rid-ley sea turtles making their way to the sea. Of more immediate interest to me were the waves, which, I was relieved to see, were of manageable size. We had the place to ourselves. For the next hour and a half, until the tide came in, Kim and I caught ride after ride as one of the other campers recorded us on Rick's digital video camera.

I returned to the camp feeling quite pleased with myself. The feeling didn't last. Watching my performance on his big-screen television over lunch, Rick, a k a Sergeant Surf, made no attempt to disguise his scorn as he enumerated my failings in excruciating detail. My weight was too far forward on the board. My paddling was all wrong. And look at the way my legs flopped around when I tried to catch a wave, throwing everything off balance. Why, I was practically a guppy, to use Rick's most deprecating term. I wanted to hang my head in shame.

After the video, Rick sat down with me at a table and patiently repeated the rudiments of surfing that he had outlined for the others while I was off by myself on our first day. (Sample tip: For maximum efficiency while paddling, keep your shoulders up and fully extend your arms for every stroke.) I listened carefully and, back on the water that afternoon, began to put his lesson into practice. Conditions were ideal, with a new swell filling in and the wind -- uncharacteristically for that time of day -- blowing stiffly offshore. Long pennants of spray trailed from the wave tops. Waiting for my chance, I spotted a good-size peak and spun my board into position. Something clicked. A few quick strokes, a smooth transition from prone to standing, and suddenly I was flying, catapulted down the line just ahead of the fast-peeling curl. I had finally caught my perfect wave. I carried my board out of the water in a state of utter bliss.

A day or two later, reviewing my video-recorded performance after another session, Rick paid me the ultimate compliment. "Man, you were ripping."

There were more good days. Every time I paddled out I seemed to gain a little confidence. I was no longer afraid to try a late takeoff, catching the wave at the last instant as the lip began to feather and pitch forward. Now and then I managed to bounce my board "off the lip," steering high into the crest of the wave after a hard bottom turn. I missed fewer waves. I wasn't a guppy anymore.

But I wasn't a teenager, either. Thanks to Deanna and copious amounts of ibuprofen, I'd managed to stay more or less functional throughout the week. On the second-to-last day of our stay, however, I was trying to position my board in front of a peak when I twisted my torso a bit too hard, producing a disconcerting pop from somewhere in my side. I thought I'd just pulled a muscle and kept surfing; three weeks later, my internist would diagnose the problem as a probable cracked rib. The next morning I racked up another injury when, as I was standing in the shallow water after a long ride, a gust of wind scooped up my nine-foot fiberglass board and tossed it into the air like a candy wrapper. The edge of the board came down squarely on my shoulder, with excruciating results. It seemed like a good time to leave.

We flew out of Nosara that afternoon, banking up amid the clouds with a last, lingering look at the swells wrapping around the north headland and into Guiones Beach. Two days later my shoulder had turned an impressive shade of purple and I was sitting at my desk back in Washington. It was then that I got an e-mail from Dave. It said simply, "All I can think about is surfing."

I knew exactly what he meant.