Floating amid mega-yachts in Monte Carlo’s crowded harbor during the May 2015 Monaco Grand Prix was a startling sight: Windstar’s 212-passenger Star Breeze cruise liner. Lodged in one of the prime berths, the passenger ship was placed as a private yacht would be—because for the week, it was one.

“The ship is within inches of not being able to come into the harbor, but it fits exactly, down by the hairpin turn,” explained Windstar’s Amy Conover via phone from her office in Seattle. The 440-foot long Star Breeze wasn’t crammed with day- trippers midway through a jaunt around the Mediterranean, for which it was designed. The ship was serving  as a private playground, rented by a wealthy client for use as a convenient perch for 200 friends while the ship’s crew catered to their needs. Guests could sleep and party aboard it during the week of Monaco's famed car races, enjoying the comforts of the waitstaff and kitchen crew amid watertight security. The mogul renter even provided the most luxurious of day trips: Each of his lucky friends was offered a vintage automobile from the likes of Mercedes and Ferrari, including some retired Grand Prix race cars. Guests drove the race course on Saturday evening during the moments before it was shuttered to make way for Sunday’s grand finale.

Such ships have long been rented out for corporate charters, perhaps as end-of-year incentives for top-performing sales execs or as vehicles for political fundraising. Today they are increasingly taken out of public use for private hire, enabling billionaires such as that Grand Prix super-fan to upgrade to a personal cruise ship.

“It’s like owning a mega-yacht for a week or two,” explained Carolyn Spencer-Brown, editor of industry bible Cruise Critic, via phone as she was about to board a ship in Miami. “It’s much like if your first-ever flight was on a private plane. You’re starting at the top.”How Much Does It Cost?

Speaking of the top: A seven-day trip on one of Windstar’s 212-passenger Star-class ships could cost from $600,000 to $1 million; Crystal Esprit’s private-hire rates start at $500,000 per week. To charter the super yacht, you could pay $731,000 for the same time frame. Windstar’s prices don’t include surcharges of around $70,000 per stop at such popular ports as Edinburgh or Venice, Italy. Unlike a yacht, though, private chartering of cruise ships comes at all-inclusive rates, with no additional tab for food and drink, taxes, entertainment, or fuel surcharges. Even gratuities are included.

It’s enough of a growth market that it’s influencing the design of vessels newly ordered by many major lines. (See, for example, Crystal’s 62-guest Crystal Esprit, which made its debut in December, tailor-made for private charter. Since 2010, France's Compagnie du Ponant—which just joined Gucci Group, Christie's, and Château Latour as part of François Pinault’s Groupe Artémis S.A portfolio—has added four vessels to its fleet, each with just 132 cabins. Again, this is the ideal size for private hire. (Anthem of the Seas, the most recent addition to Royal Caribbean Cruises Ltd.'s fleet, has space for almost 5,000 passengers). With butler service and a tiny, tony spa, the designs of the trimmer vessels are inspired by those of private yachts.

Given the rates of custom hire, it’s not surprising the lines are keen to snare more private clients: even if Crystal fills Esprit to capacity – perhaps on a trip from Athens to Dubrovnik, with 75 passengers paying $6,230 each, that still only earns the firm $467,250 in a week, compared with snaring a half million dollars from a single client over the same period. Most dedicate a full-time staffer to oversee charter programs. Yet, notwithstanding daily inquiries about such private hires, most of the lines are oddly secretive about this revenue stream, preferring discretion.A Quiet Habit


“Seabourn is not interested in providing this information and will have to pass on this opportunity,” sniffed one corporate spokesperson via e-mail in response to queries from Bloomberg. Rival Celebrity Cruises was equally evasive, though it did confirm after multiple e-mails that its 100-person ship, Xpedition, has been privately chartered. In part, companies fret that regular passengers might be deterred from booking if there’s a chance that a favorite ship might be off-limits for several weeks, though such charters are customarily planned two or more years ahead of time and rarely interfere with regular sailings. It’s easy to spot when a commercial ship will be offline for a private charter: Browse its year-long sailing schedule and look for weeks in which a vessel isn’t on offer and has probably been hired as a private, floating playground.

Renting an entire ship for the week puts no limits on what you can do, on or off the boat, according to Bruce Setloff, head of sales and charters for Crystal cruises. A wealthy Brazilian family hired the Crystal Esprit for a summer vacation tour of Croatia and the Mediterranean. “They asked us to clean the beaches at every port before they arrived, so we hired people to go and pick everything up, especially when they had to go to public beaches at a few of the ports,” Setloff said by phone from his Century City, Calif., offices. Celebrities Love It