IT’S FAMILIAR BUT DIFFERENT, old but radically new. We’ve seen it before, but never so vibrant, so vivid, so immersive, so romantic. It’s a painting by Gustav Klimt, freed from its frame, sliding across the walls, warping, magnifying. Where are we? We’re in the middle of Klimt’s The Kiss. Where are we exactly? We’re in a bunker on the island of Jeju off the southwest coast of South Korea.

Confused? Get used to that. This island is never quite what you think it to be. Rustic traditions coexist with flashy modernity. Plastic expanses of hothouse farms stretch inland from a dramatic coastline dotted with glossy tourist resorts. An island fringed by gentle flatlands is dominated at its center by Korea’s tallest mountain. Even the climate is subverted: The nearby mainland endures freezing winters and sweltering summers, while Jeju remains relatively mild year-round.

Thanks to its scenery and weather, Jeju has long been the top domestic destination for South Koreans. The island’s population of 660,000 is supplemented by more than 15 million tourists each year, including increasing numbers from China (Jeju being one of the few places in the world the Chinese can visit without a visa).

As with any tourist hub, new attractions always spring up, mostly on the popular south coast. An old military bunker in the town of Seogwipo has been reinvented as the “Bunker of Light,” and here the Klimt display is currently exhibited. For the duration of each 30-minute show, the cavernous interior is awash with color and music. Visitors wander through it, spellbound.

Jeju boasts to be “the land of a hundred museums.” Not all prove as tasteful as the Klimt exhibit. Among many others, you’ll find museums devoted to teddy bears (displays recreate famous events from world history with teddies), seashells, chocolate, optical illusions, Greek mythology, African art, computers, aviation, automobiles and sex. The latter is celebrated at Jeju Loveland, set within a park scattered with X-rated kitsch statues.

Love is a common theme on Jeju. As South Korea’s No. 1 honeymoon destination, many of its attractions and resorts specifically cater to young couples, usually in a more cutesy and innocent manner than Loveland. If the saccharine sweetness becomes overbearing, you can escape into the island’s mysterious wilds.

A new, 264-mile hiking route, the Jeju Olle Trail, circumnavigates the island in 25 manageable sections. Be prepared for changeable weather. Jeju’s climate, while benignly mild, is also damp. Fog and rain often drift in off the Korea Strait, softening the landscape.

On a misty, drizzly day, the interior of Jeju acquires a special mystique. Look along the marked trail. Periodically, strange, stylized human shapes appear through the gloom, sometimes less than knee-high, sometimes taller than you. These are Dol Hareubang — stone grandfathers. Intended to ward off evil spirits, they are carved out of gray volcanic rock and positioned at house entrances and throughout the landscape (you’ll also see them in myriad forms in the souvenir stores).

These odd sculptures provide the most visible evidence of Jeju’s indigenous culture, ostensibly Korean yet also something else. The Jeju dialect is symbolic of that; a version of Korean with so many odd pronunciations and unique words, mainland Koreans are unable to understand it. This local language is now in decline, with perhaps fewer than 1,000 native speakers remaining.

Sunrise Peak © ZKRUGER | DREAMSTIME.COM

Also in decline are the haenyeo, Jeju’s remarkable female divers. For centuries they have made a living free-diving the treacherous coastal waters to collect shellfish, sea urchins and abalone. Their working day has been formalized into a daily show at Sunrise Peak, a scenic spot on the east of the island. Here, twice a day (1:30–2:30 p.m. and 3–4 p.m.), spectators can watch these women plunge to depths of 30 feet or more, surfacing long minutes later with their catch.

Tourism helps to preserve the haenyeo culture but threatens to undermine some of the other elements that make Jeju so special. The southern coast, especially around the town of Seogwipo, is the main focus for the tourism industry, yet the island’s gateway — by air and ferry — is Jeju City, in the north.

A new airport currently being planned in the south could triple visitor numbers to 45 million. Local activists claim current numbers are already too high and a new airport will accelerate the destruction of the unique environment that attracts the tourists in the first place.

While the arguments rumble on, tourists continue to come. Up to 189 flights arrive from Seoul every day, making it the world’s busiest air route. From the airport the new arrivals disperse across the island, finding attractions along the way. Even the road itself can be an attraction.

Heading southwest from Jeju, close to Loveland, we see signposts for the “Mysterious Road.” When we reach it, all we find is a modest stretch wending through countryside. No spectacular views, no gaudy tourist facilities. However, this road appears to defy the laws of physics. Stop, switch off the engine, release the brake. We’re facing up the hill, right? So why are we rolling forward, gathering momentum?

We experience the phenomenon while sitting in the vehicle, and then get out to test it by rolling a can along the asphalt. The results are repeated: Here, everything seems to roll uphill. The mundane truth is we’re witnessing an optical illusion. It’s a perfect introduction to Jeju, where not everything is at it seems.

Jeju Island Info to Go

Flights arrive at Jeju International Airport on the north coast, three miles west of Jeju City. Bus transfers from the airport to the tourist resorts on the south coast take 80–90 minutes. Alternatively, regular ferry services to Jeju run from the mainland ports of Mokpo and Busan. The crossing takes 4.5 hours from Mokpo and 12 hours from Busan.

Where to Stay in Jeju Island

HIDDEN CLIFF HOTEL AND NATURE The name explains it: This 250-room hotel sits within a beautiful forested valley that opens onto a stretch of coastline. Striking design makes the most of the surroundings. 542, Yeraehaean-ro, Seogwipo $$$$

LAREEM BOUTIQUE HOTEL With sleek, 1960s-style modern architecture, the boutique hotel offers an intimate alternative to the nearby mega-resorts, though you’ll need your own transport. Request a sea view. 39, Daepyeong-ro, Andeokmyeon, Seogwipo $$$

THE SHILLA JEJU This Jeju outpost of the highend Shilla hotel chain adjoins one of the island’s prettiest beaches. The architecture presents a Mediterranean theme. 75 Jungmungwangwang-ro, 72beon-gil, Seogwipo $$$$

Restaurants in Jeju Island

CHILDONGA The black pig is indigenous to Jeju. This unpretentious barbecue restaurant proves a great place to try the famous black pork — cook it at your table. 1507-10 Donghongdong, Seogwipo $$$

GIEOK I AM HOUSE Jeju is renowned for seafood, especially the abalone caught by courageous female divers. This restaurant serves it as fresh as can be: alive. 6 Jungang-ro, Seogwipo $$$

MOM’S TOUCH South Korea’s answer to KFC, though here there isn’t just one secret recipe for the fried chicken, there are 24. A cheap and tasty option. Outlets throughout Jeju Island $$