SOUTH HUTCHINSON ISLAND is not just a physical barrier island, but a metaphorical one as well - the kind of barrier people like to put between themselves and the often frenetic pace of the South Florida mainland.

A finger of mangroves and sand, the island stretches some 25 miles north along the Atlantic coast from about 45 miles north of West Palm Beach. At some points, it is barely wide enough for a two-lane road, the beach and some stray palm trees. At others, it bubbles out westward into the Indian River enough to squeeze in the familiar gated developments seen throughout southeastern Florida.

Three bridges connect the island to mainland Florida, but the showy scene of the Palm Beaches and points south feels leagues away. "We like it because there's no glitz," said Ginny Deckelman, of East Northport, N.Y., who, with her accountant husband, Charlie, bought a condo on the island 14 years ago for sneaking away during the months outside tax season.

Her assessment is an understatement. While many residents have deep pockets, the only glamour came with the singer and actress Frances Langford, a veteran of Bob Hope's shows for the military who died last year (and whose beach house is on the market). Celebrities don't appear to be rushing in to take her place.

The only thing that rushes on this island is the surf, which mixes with the pungent aroma of the mangroves. Even during Christmas week, few cars were on the road. A handful of bikers and joggers were enjoying the low-70's temperatures. On the beaches, families strolled, couples nuzzled, and a lone sandpiper skittered across the golden shore.

The Scene

South Hutchinson Island is residential, with no town and little commercial development. The southern third, which lies in Martin County, is solidly built with a mix of condo developments and single-family homes. The largest part of the island, to the north in St. Lucie County, allows high-rises, which make it feel more densely developed.

Outside the exclusive enclave of Sailfish Point at the southern tip, where perfectly groomed poodles trot alongside well-heeled owners wearing white pants and button-down shirts, the island is very casual.

"We wanted to be comfortable wearing a bathing suit most of the time," said Bob Conway, 78, a Cincinnati businessman. That's easily accomplished. Except on the golf course, the typical activities - boating, beach-strolling, fishing (the area is the self-proclaimed sailfish capital of the world) - tend to be Speedo-only.

Mr. Conway and his wife, Ruth, bought one two-bedroom condo in 1983 for $190,000 and a virtually identical second one in 1990 for $550,000 - a testament to soaring prices, which have continued to rise since then. He jets down several times a year for a few weeks at a time and often turns over the house keys to his 8 children and 19 grandchildren.

More than half of the island's residents are part-time. They come for relaxation and nature - and find plenty of both. Public beaches break up the developments that line the oceanfront, and several miles of the northern half boast nothing but low-lying scrub (with the incongruous exception of a nuclear power plant). Herons and egrets feel at home, a plus for Mr. Conway. "We're avid birders," he said, "and the island's great for our hobby."

The island lies just over a bridge from the town of Stuart at its southern end; in the middle, from Jensen Beach; and at its northern end, from Fort Pierce. To the north, across a narrow channel of sea, is North Hutchinson Island, not a twin but the southern tip of a long spit of land that lies off the Florida coast, bearing various names in different places.

Real estate agents estimate that up to half of South Hutchinson Island's part-time residents come from well north of Florida, many of them retired or near retirement, and sometimes rent out their homes during the summer. The other half tend to be young, successful and from South Florida, using the island as a weekend retreat and sometimes renting out their homes in winter.

Bob Paradela, a 41-year-old trial lawyer from Coral Springs, and his wife, Jennifer, 39, a management consultant, first bought on the island in 2004, purchasing a two-bedroom oceanfront condo for $399,000. That's on the market right now for $625,000 because they recently traded up to a 2,200-square-foot three-bedrooom, for $745,000. They rent out their place during the winter and, with their two children, use it every other weekend in the summer. "It's close, and it's significantly quieter than the rest of South Florida," Mr. Paradela said. "And, well, it's the beach."

Pros

This is a quiet, laid-back place. The beach and ocean are never more than a few steps away.

Though there is just a single two-lane road, there's never a traffic jam, even in high season.

It's easy to get off the island and into the towns.

Cons

While there are a couple of decent restaurants and a supermarket, most services require a drive to the mainland.

As a barrier island, South Hutchinson takes the brunt of hurricanes. Many homes were damaged the last two seasons, and the local Holiday Inn was so ravaged by Frances and Jeanne in 2004 that it was shut down and sold.

The Real Estate Market

Most of the island's homes are condos, the vast majority with two bedrooms. A much smaller group have three; a handful have only one. While it's possible to find a small one-bedroom condo for less than $150,000, they are rare. Most two-bedroom units start in the $400,000 range, and three-bedrooms at more than $500,000.

Prospective home buyers have a couple of decisions to make. First: oceanfront or riverside. It's possible to save a couple of hundred thousand dollars by living on the side of the island that faces inland, bordering the Indian River. Next: low-rise or high-rise. Martin County imposes a four-story height limit, but cross into St. Lucie County and tall condo buildings appear immediately. The limit is 125 feet, and new high-rises continue to go up.

Many buyers prize the smaller buildings, but the high-rises have their fans. Bill Kelly, a retired New York City police captain, and his wife, Annemarie, started in a Martin County condo in 2001 but sold it two years later. ("We made a lot of money," Mrs. Kelly said.) They used the profits to switch to a condo in a St. Lucie County high-rise where they have views of both ocean and river.

Prices all over the island, as in the rest of South Florida, have soared the last five years, doubling in the last three. A two-bedroom condo that might have sold for $150,000 in 2000 will now fetch $500,000. But agents agree that the market is cooling off. Homes are holding their value, but places that would have sold in two days a couple of years ago are now remaining on the market for two to four months, they said.

While buyers have made plenty from recent sales, that doesn't mean everyone is selling. Mr. Conway, the birder and businessman, plans to pass his property along to his children. "Then the kids can do whatever they want with them," he said. "Maybe sell them and buy some vacation property of their own."