How to behave as a superyacht guest

• The world's most extravagant yachts are in the Mediterranean to kick off the summer season.
• Uber-rich boat owners often use their toys as a place to entertain lucky guests.
• For those with an invitation from a billionaire, here's a guide to the etiquette of superyachts.

The yachts owned by billionaires like Mark Zuckerberg, Jeff Bezos, and Barry Diller have all made their way to the Mediterranean for the 2024 summer season — and their lucky guests won't be far behind.

Each year, the wealthy invite their friends to join them aboard their palaces at sea, creating a sort of summit of the rich and famous.

Last year, Bezos' yacht Koru was the venue for his engagement party, which reportedly drew guests including Bill Gates, Ari Emanuel, and Leonardo DiCaprio. Eos, owned by billionaire Barry Diller and fashion designer Diane von Furstenberg, played host to Candice Bergen, Emma Thompson, and Jason Blum. Meantime, Giorgio Armani held a party on his yacht for the likes of Sydney Sweeney and Kerry Washington.

Being a guest on a superyacht is probably the best kind of guest to be — but the etiquette aboard the multimillion-dollar vessels comes with its own idiosyncrasies.

Aside from basic safety guidelines, most of the rules of superyachting are unwritten. The very few who need to know them — there are only about 5,800 yachts longer than 30 meters at sea, according to SuperYacht Times — already know them.

But if you do happen to be the rare lucky guest of a party on the water or find yourself included in a $1 million-a-week vacation, there are a few things you need to know.

After touring superyachts that sell for as much as $75 million and chatting with the people who buy, sell, and work on them at the Palm Beach International Boat Show, Business Insider gleaned a few key edicts. Given the discreet nature of the industry, almost all the people we spoke with requested anonymity to protect their working relationships, but here's what they had to say.

Take off your shoes

While it's a basic rule for anyone in boating, it may come as a surprise to an outsider that no matter how much money you have or how expensive your heels are, in the vast majority of cases, you can't wear shoes on board.

It's partly for safety — you don't want anyone slipping on a wet deck — but partly to keep the yacht clean. So expect to see barefoot billionaires, and if you forgot to get a pedicure, bring a set of special boat shoes.

Don't make any assumptions about money — but know the signs

In the superyacht world, it's safe to assume almost everyone you meet is very, very rich, and many brokers and builders say you can't judge a book by its cover when it comes to prospective clients.

"It has nothing to do with how they're dressed," one broker told BI. "It's the biggest mistake you can make because a complete slobby-looking guy or couple could be a multibillionaire."

There are, however, a few clues. Watches are one; new footwear is another.

"Rich people always have new shoes," a superyacht expert said. But because of the shoe rule mentioned above, this tip probably applies only when they're on land.

Book your massage early

Wellness areas, including spa rooms with a massage bed or two and a professional-grade facial machine, are becoming must-haves on superyachts. Most have a customized spa menu and a crew member who doubles as a trained masseuse or beautician — and they're usually in high demand.

One captain said he'd implemented a booking system to ensure people weren't fighting for the same spots. A broker said sometimes masseuses would be so busy they wouldn't leave the small spa cabin for hours on end.

So, if you want to make the most of your relaxing time on board, reserve your pampering slot as soon as you get your welcome cocktail.

Pirates are more real than you'd think, and many superyachts have hidden safe rooms

While you might dress up as a fake pirate for an onboard theme party, there are very real ones — and other dangers — on the high seas.

In certain areas, including parts of the Indian Ocean and the Gulf of Aden, pirates are a cause of concern. In the Red Sea, owners are concerned about the Houthis.

Superyachts can come equipped with sonic weaponry, lockdown systems, and anti-drone protection. Builders are even designing safe rooms — which are apparently just as plush as the rest of the ship.

The longer the boat, the closer to $1 billion

While you can't judge a buyer based on appearances, you can judge them on the length of their boat.

One rule of thumb: If someone has a brand-new 50-meter vessel, chances are they have $1 billion to their name. If it's over 100 meters, expect the owner to have at least $2 billion. And for a boat bigger than that — like Jeff Bezos' 127-meter megayacht Koru — it takes many, many billions.

Money can't buy you everything

The world's biggest, most expensive yachts are custom-built by shipyards that produce only a handful of boats a year.

But no matter how many tens of millions of dollars clients are spending, there are things to which builders will refuse to say yes.

"In the end, the boat has our name," an executive from one of the world's biggest shipyards told BI.

They recalled a client who requested a yellow hull to match his Lamborghini. The shipyard declined, steering the client in another direction.

"If I don't like it, I don't build it. I finalize two or three contracts a year," another builder said. "If somebody can say your vessel is ugly, my reputation is bad."

Yacht crews are trained to make the impossible possible. A guest requests fresh caviar flown into the middle of the Caribbean? No problem. Fresh flowers every day while at sea? It'll cost you, but it can be done.

But they can't time travel, and captains and crew members say the thing that causes the most friction is when a client or owner wants to go from point A to point B — right now.

"The hardest request is when they want the boat in a place — yesterday," one captain said.

The best person to know? A friend with a superyacht

Superyachts are expensive to build and expensive to maintain. According to the industry standard, owning a superyacht will cost 10% of its new-build price annually. For a $100 million yacht, that's at least $10 million yearly going to crew, regular maintenance, insurance, fuel, and dockage.

Chartering, too, is costly. Beyond the list price, which can be hundreds of thousands a week, guests must pay for provisions, which are pegged at 35% of the charter fee, and are expected to tip between 10% and 20%.

So the most important unspoken rule of superyachting is actually that the only thing better than owning a superyacht is knowing someone else who does — and invites you along, of course.