HE bikes wait in the hull. Miller Genuine Draft flows from golden cans. A piano player, knowing his audience, segues from "Hotel California" to "Bohemian Rhapsody." In Dizzy's Lounge atop Royal Caribbean's Explorer of the Seas, a gang of bikers considers the itinerary for a weeklong Caribbean cruise just underway: Wednesday in St. Maarten; Thursday in St. Thomas. First up is San Juan, P.R. On Tuesday we ride.

"Our tours are not the usual tours," promises Steve Wallach, organizer of the Harley Cruise. He speaks into a microphone to be heard above the piano. "We will not just be riding past government buildings or anything like that. We will be stopping to shop. And yes, we will be stopping at bars."

Cheers wash out the classic rock. Glasses clink. Tattoos are compared: a black scorpion inked on the triceps of Bob Earley, a firefighter from Winter Springs, Fla.; the block letters "Harley" and "Davidson" snaking down the right arm of Barry Nelms, who owns a bar in Poplar Branch, N.C. Most of the bikers have never met before. All have gathered on this ship for a vacation so perfectly attuned to their desires they can barely believe it.

"It's just about he neatest thing in the world," says Bill Liptak of West Palm Beach, Fla., who goes by Bad Billy. "I mean, where else can you get on a boat, go to different countries and just ride without worrying about red tape or anything?"

Nowhere else, actually. While theme vacations for motorcycle enthusiasts are as common as other "niche cruises" aimed at bluegrass musicians or, say, readers of The Nation, Mr. Wallach is the first to offer a benefit not found on other Harley cruises: His clients are allowed to take their own bikes on board; on other full-size cruise ships, passengers must rent bikes at each port of call.

"Your own bike is everything," says Pam Griggs, a passenger and a paralegal from Grandy, N.C. "Any of these guys, they know every click their engine makes, they know the sound of their muffler. If you put them on a strange bike they have no idea what they're in for."

On each of six annual Harley cruises, up to 70 people take as many as 35 bikes onboard. Each passenger is paying $1,100 to $1,500 for a stateroom bed, a bit more than regular passengers pay. Included in the premium are a few perks. Harley riders, personally rolling their bikes off the ship, are the first off every port. At the mandatory immigration check on St. Thomas, the bikers skip to the front of a long line of other passengers. White luggage tags are distributed at the end of the cruise, allowing the bikers to clear customs first.

Attendance on the first cruise of the season, in December, is down slightly. Although the ship has sold out, some bikers have stayed home to repair houses ravaged by the hurricanes that struck the Southeast. Those who make it onboard include a trio of firefighters, the owner of a construction company and Nolan Clark, a heavy-equipment salesman from Fredericksburg, Va. With his bushy mustache and blond hair matted down by a black baseball cap, he's the spitting image of his idol, Dale Earnhardt.

"I like to say it clears out the cobwebs," Mr. Clark says of the time he spends on his black-and-silver Road King Classic. "You ride for 15 minutes after work, and you just forget about everything that was botherin' you."

The ship glides out of Miami on a Sunday evening. Fading sunbeams reflect crimson neon onto the windows of Miami Beach. Monday is a sea day, free time to pound daiquiris, lose at blackjack and watch professional figure skaters wobble on an undulating sheet of ice. The weather is tropical, and warmer with each mile from port. Flying fish soar away from the ship's hull. At night, meteors streak across the sky as if carried by the firm breeze.

With only a few dozen bikers dispersed among 3,100 other passengers, this isn't Bike Week at sea. There is no female coleslaw wrestling on the Peek-a-Boo bridge, for instance. There's only a random black Harley T-shirt spotted on the line for the buffet, mingling with tourists from Shanghai, Shreveport and Quebec City. A tribal tattoo winds around the arm of a woman tanning poolside. In the karaoke lounge, Earle (Buddy) White sings Toby Keith with a Carolina drawl.

San Juan is the first port, on Tuesday morning. As the ship slowly docks, the bikers gather in the hull. Dressed in chaps and heavy boots, they unstrap Sportsters and Heritage Softails from stabilized racks. Crew members ask to have their pictures taken with the bikes. When the door opens, Bart Bornack of Kissimmee, Fla., rolls off with his girlfriend, who wears a leopard print bikini top, cut-off denim shorts and a black helmet affixed with instructions to "Bite Me!"

State police, blue lights flashing on their own bikes, stop traffic as the Harleys roll out of the port onto the highway. Stop signs and traffic lights are ignored. It's the type of treatment usually reserved for heads of state, and the bikers are outranked only once, by a motorcade bearing Puerto Rico's governor. One pedestrian salutes with a middle finger.

The bikers wind along the coast, past waterfront cemeteries and an indoor cockfighting arena, down to Piñones Beach. Turquoise waves break on a coral seawall. A dog subdues a green iguana fully half his size. Revving engines cause a girl and boy, neither older than 3, to explode into aerobic spasms of joy.

The bikes park along a row of thatch-roofed shacks. Entrepreneurs drop rolls of cornmeal and crayfish into caldrons of fat, selling the greasy results - alcapurias con cangrejos - for $1 apiece. Inside El Pulpo Loco bar, salsa rhythms set a soundtrack. Plastic cups of Presidente beer are drained, refilled, then drained again.

"We'd been on a couple of cruises before," says David Smith of Columbia, S.C., the owner of a yellow Road King he assembled with parts acquired on eBay. "We'd get off the boat at San Juan, go into the first bar we came across and park it there for the rest of the day," he said. "With this you get to roll around the whole island."

Leaving Piñones, the bikes, which rode two abreast on the highway, narrow to single file for the cobblestone streets of Old San Juan. As the procession winds from El Morro back to the boat, tailpipes roar loudly enough to trip car alarms. At the pier, Mr. Wallach reminds the bikers (for at least the fifth time) to absolutely, definitely not smuggle drugs onto the ship.

"Whatever you do on the island is your business," he says, stern as a schoolteacher despite his long hair and work history as a rock-music roadie. "But I'm telling you, if you do try to bring stuff onboard you will be caught and you will be prosecuted and we will all be in a whole lot of trouble."

It took Mr. Wallach two years to set up his Harley Cruises. He needed to negotiate with port agents, pier agents, multiple governments and officers at Royal Caribbean, the only cruise line he's affiliated with.

"We had to first get approval from one agency before we were able to move on to the next agency, then so on and so on until all the agencies were in sync," he says. "We had to ensure that all of the necessary paperwork for each motorcycle and operator were valid and that our company ensured that all matters pertaining to safety, both on a ship and on each island, were properly set."

The Harley-Davidson company declined to officially bless the cruise, a matter that hasn't stopped him from already selling out some dates for the 2006 season. He just started a fall cruise-and-bike-tour up the New England coast into Nova Scotia. Starting in 2007, Mr. Wallach plans to offer a second Caribbean Harley Cruise to Kingston, Cozumel and other western Caribbean ports.

"It's good for tourism; it's good for local businesses," says Theo Heyliger, tourism commissioner of St. Maarten, the cruise's second port of call. "This is niche marketing that we want to grow."

The St. Maarten ride begins early Wednesday morning. Leading the tour are a local gang known as the Caribbean Eagles, its members dressed in weathered black leather vests. Stops include the island Harley dealership, the Iron Horse Saloon and a scenic overlook where Bart Bornack parks his deuce to snap pictures.

"We got time to slam a few beers?" he asks, eyeing a roadside shack.

A motorcycle provides a chance to see and feel the island in a way that can't be matched in a car. It's easier to catch the details: thousands of miniature yellow butterflies fluttering in bushes; a goat silhouetted atop a ridge; a wrought-iron lattice entwined with flowers.

An island radio station tracks the parade as it winds from the Dutch side of the island into French St. Martin. Whenever the road stretches out a bit, engines open in a blast of muscle. Schoolchildren in pink uniforms follow the noise across a playground, poking hands through a chain-link fence to wave. The irresistible rumble prompts mechanics to drop tools and run to the road.

"I like riding through the neighborhoods, looking into the different houses as we pass," says David Smith. "You get to see all these people come out of their houses, and you can tell that your bike easily costs more than their house does. It makes you think."

As the riders climb over a crest, a stunning vista unfolds. Pastel houses decorate steep green hills like ornaments on a Christmas tree. Sailboats dot the bay like confetti dropped on Times Square. The trip ends at a beach on the French side. Bare toes dip into the sand. Pork and rum punch are shared with the Caribbean Eagles.

"I've been to St. Maarten like 10 times but this is the first time I've seen something like this," says Vida Burns of Columbus, Ohio. "It's not touristy. It's from locals that you get the stories about the island, you get recommendations on cool places to eat, you meet wonderful people. You don't get that on the boat."

The Harleys rode in three of four ports the ship stops at, with Nassau the only exception. It's possible to rent bikes at each stop where the group rides, though Harleys are heavy and require skill to operate; one novice renter who joined the ride only in St. Maarten laid down his bike three times, once when a goat darted in his path. It's also permissible to take Hondas or other motorcycles, though no one has yet had the guts to do so.

It's not a cheap trip. For two people on a seven-day cruise, incidental purchases - a few cocktails at bingo, a Spinning class, onion rings at the Johnny Rocket's restaurant - can easily surpass $1,000. Add massages, scuba lessons and a heavier payload of alcohol and the costs can quickly double.

With Mr. Wallach the only provider of such trips, the riders must accept his occasional shortcomings. Mr. Wallach promised that the longest of the three rides would last 120 miles, yet that was the total mileage for all three rides. A lunch buffet in St. Maarten cost $50 a couple for a meal that was worth $15 at most. A few of the riders were so nonplussed by the first two excursions that they skipped the final tour of St. Thomas.

"If they'd told us we'd only get to ride 20 m.p.h. tops, that we'd be on uneven, jagged roads, and that we'd be parking on sand every day, I don't think I would have come," complains Bob Earley, the Florida firefighter, who spent the last riding day shopping with his wife and working out in the ship's gym.

Which was a mistake. St. Thomas featured the best roads of the three islands. Twisting trails climbed quickly to a mountain lookout over Meaghan Bay. Speeds wound into the 50's.

"I had tears coming down my eyes," says Pam Griggs, back aboard the ship after the St. Thomas ride. "All week I said to myself that I can't believe I'm in San Juan. I can't believe I'm on a motorcycle in St. Maarten and then St. Thomas. We had spent so long thinking about it and planning it and talking about it, and here we all were actually on the islands, on our own motorcycles."

Ms. Griggs and her friends are so delighted by the cruise they're already talking about a return trip next year.

"And we're all thinking of getting tattoos to commemorate our ride," she says.

For the Bikers of the Caribbean, can there be a more perfect souvenir?

Cruise Information

All the spots for the remaining Harley cruises in 2005 - Feb. 6, March 6, April 17 and May 15 - are sold out, with one exception: A few of the highest-priced ($1,059 per person, double occupancy) ocean-view staterooms are still available for March 6.

Bookings are now being taken for next season's sailings, which include Dec. 11, 2005, and Jan. 22, Feb. 5, March 19 and April 16, 2006, and a yet-to-be-determined date in May 2006.

Costs, per person in double occupancy, vary depending on date of departure and quality of cabin. The least expensive of the coming trips is $978 for an inside stateroom on the December 2005 cruise and the most expensive is $1,718 for a junior suite with balcony on the April 2006 cruise. The prices do not include air fare.

For more information: Steve Wallach, Entertainment and Travel Alternatives, (888) 711-7447; w