Mario Salcedo doesn’t remember exactly when it started—it could’ve been after the first 100 cruises, or 500, or 900—but it’s still a bit of a problem. On one of the rare days he finds himself on dry land, his legs sway involuntarily, bracing for the movement of the ship they’re accustomed to having underfoot.

“When I walk from my kitchen to my living room, I stumble,” Salcedo, 66, tells mental_floss. “I can’t walk a straight line. I’ll run into the wall. I spill coffee.”

He has self-diagnosed the issue: “I’ve lost my land legs.”

More than 7000 days at sea will do that to you. For the past two decades, Salcedo has been a full-time occupant on cruise ships, spending less than two weeks out of the year at his condo in Miami, Florida. The rest of the time, he's taken up a floating, permanent residence on the numerous megaton cruise ships sailing out of Florida on the Royal Caribbean fleet. He dances. He scuba dives. He answers endless questions about the best restaurants on board. He operates a small business from his cabin. And he couldn’t be happier.

Royal Caribbean

When Salcedo was 7 years old, his parents fled the hostile political climate of Cuba to relocate in Florida. In college, he studied finance and economics, putting down roots at a Miami multinational corporation. The corporate ladder was lined with palm trees, but he was never in the office for very long.

“I racked up three million frequent flyer miles,” he says. The company sent him all over the world. After 21 years, 90 percent of which he estimates was spent traveling, an exhausted Salcedo decided he was finished. He walked into his boss’ office and declared he’d be leaving his well-paying job.

“Maybe you’ve been traveling too much,” his supervisor said. “Why not take some time off?”

“You don’t understand,” Salcedo told him. “I want to change my whole lifestyle.”

“Well, take a year off.”

“You don’t get it,” Salcedo said, and waved goodbye.

He knew he wanted to travel, but not by air. “I was sick and tired of planes,” he says. With a home in Miami and frequent visits to the Caribbean, he had seen cruise ships in port constantly and had always been curious. In 1997, he boarded his first ship.

“That was it,” he says. “I knew I wanted to cruise for the rest of my life.”

For the next three years, Salcedo sampled almost every cruise line and ship that he could book, searching for the right combination of amenities, atmosphere, and comfort. He sailed to Scandinavia, South America, and Europe, nibbled on the food, and interacted with crews. In January 2000, he stepped foot on the Voyager of the Seas, at the time the largest ship offered by Royal Caribbean: next to Carnival, it's one of the industry’s two biggest cruise lines. It had innovative attractions (like a rock climbing wall), generous rewards for loyal cruisers, and a staff that treated Salcedo warmly.

“I needed stability,” he says. “I picked the cruise line I thought was the best one, and it happened to be Royal.”

By this time, Salcedo had put the final touches on a financial consulting business that could be run remotely and still provide enough income to afford the $65,000 annually he needed for cruise expenses. After tussling a bit with family and friends—“They thought I was nuts to throw away my career”—he became a full-time passenger, or what the industry refers to as a “frequent floater,” booking over 800 voyages with Royal and counting.

Salcedo (third from the right) with the Royal Caribbean crew Royal Caribbean

When discussing his preferred lifestyle, Salcedo likes to reference The Love Boat—a show he believes will help the average land-locked individual understand why he has chosen to take up cruising full-time. “Watch the reruns,” he says. “Everybody’s happy. Everyone’s defenses are down. Everyone wants to have a good time and socialize.”

A typical day for Salcedo might begin with a four- or five-hour work shift, often from a deck chair near the pool and overlooking the ocean. After clocking out, he might go for a swim before heading to one of the ship’s many lounges for some salsa dancing. On every cruise, he says, there are usually 15 or 20 people he befriended on a past voyage, many of them “frequent floaters” themselves.

“We share stories, talk about where we’re going next,” he says. He follows up with some via email so they can try and coordinate meetings or swap suggestions for things to do during destination cruises to Jamaica or Grand Cayman.

In between, Salcedo gets peppered with questions from first-time cruisers who have heard through the grapevine about his permanent installation. With multiple restaurants on board all Royal ships--there are 22 on his current home, Empress of the Seas--they want to know where to go eat.

“I cannot eat like they do,” he says. “A regular cruiser will stuff themselves for seven whole days.” Salcedo keeps his weight under control by skipping meals and loading up on vegetables and lean proteins. If the captain invites him for dinner, he might splurge on a steak.

Walking, dancing, and scuba diving keep him fit. In 20 years, he’s never seen the inside of the medical bay on any ship. “I’ve never been sick a single day,” he says. “Never had norovirus, none of it. I eat smart, exercise, and I have no stress. Zero stress!”

Perhaps not coincidentally, Salcedo is a lifelong bachelor. While a transient lifestyle of cruising doesn’t appear to lend itself to relationships, he says he’s content. “I love to meet single ladies, and there’s plenty of them on cruise ships nowadays.

“Sometimes it goes beyond friendship. Two months later, they might come back to visit me.”

Voyager of the Seas Royal Caribbean

Salcedo has been on 23 of Royal’s 25 ships. Two are new to the fleet, and he hasn’t had a chance to step on deck yet. His cruises are usually booked six months in advance so he can try to keep the same cabin without having to transfer his luggage to another room. In October, he’ll fly to Barcelona to meet a ship that will cross back over to Florida.

The Miami condo—where he sometimes sways on the floor—is empty most of the time, used only when he’s transitioning from one ship to another; his car sits in Royal’s terminal, waiting for one of his infrequent layovers so he can drive the 15 minutes home. There are no friends to take it out for a maintenance drive.

“Any of the friends I had on land pretty much gave up on me,” he says. “It’s one of the downsides. I’m never home, so they just kind of wither away.” At sea, it doesn’t really matter who Miami’s mayor might be, or which new business has moved in down the street. “You wind up losing touch.”

Although Salcedo has become something of a public relations gift for Royal, he says he doesn’t receive any compensation or discounts beyond whatever’s offered to high-ranking loyalty program members. As a single occupant, he avoids a 200 percent mark-up of his cabin: it’s 150 percent. And the company is willing to hear him out when it comes to suggestions. It would be nice, he once told them, if frequent floaters could have free wireless access. At $20 a day, it adds up.

They said yes. He’s still trying to get more channels on the cabin televisions. “I’d like to watch Fox News,” he says. “But there is no Fox News on Royal.”

It’s a minor inconvenience. Salcedo is booked for the next two years and has no plans to permanently disembark anytime soon. “I feel better at 66 than I did in the corporate rat race in my 30s. I’ll keep cruising as long as I’m healthy and as long as I’m having fun.

“I’m probably the happiest person in the world.”