When the Carnival Freedom sets sail from Florida next February for an eight-day cruise to Panama, it will offer the same amenities as any other Carnival cruise: three pools, a jogging track, a 1970s dance club and a cigar bar.
But there is one stark difference. Passengers on the white behemoth of a ship, which can carry 2974 passengers, will enjoy those facilities naked.
The ship's expected nude sailing - the trip is 70 per cent booked - underscores the vitality of the US nude tourism industry, which the American Association for Nude Recreation says brings in around $US440 million a year, up about 10 per cent in the last decade.
"I think when we vacation, we would rather travel with like-minded people, whether nudists or jazz music lovers," said Nancy Tiemann, owner of the nude tourism company Bare Necessities, which is arranging the cruise. "It's not just about getting on a cruise ship and taking your clothes off."
Nude tourism isn't a new concept: Tiemann started booking cruises two decades ago with a ship of 600 people and the American Association for Nude Recreation celebrated its 80th anniversary last year.
But the industry has evolved, with resorts becoming more upscale, cruises getting larger, and judging from the turnout of vendors at the first nudist expo last week in Las Vegas, no shortage of tourism companies aiming to cater to those who would rather travel in the buff.
Smaller nude cruises have visited the Greek Islands, Croatia and the Italian and French Rivieras in addition to more conservative locales such as Egypt - though travellers were clothed when they toured the pyramids.
Nudists, who say they are not about forcing nudism on others, emphasise the nudist lifestyle is simply about enjoying oneself without the social or physical burden of clothing in a non-sexual, family-friendly environment of like-minded people.
"That whole joyous experience of the healthy human body is what we're all about. And adult entertainment is not nude recreation," said Susan Weaver, president of the American Association for Nude Recreation.
Nude tourism appears to be growing in popularity. A survey of US households with income of $US50,000 or more last year showed that 17 per cent of respondents saw a visit to a nude or clothing-optional resort as extremely or very desirable.
Those figures were up from 12 per cent a year earlier, according to the Portrait of the American Travelers Survey of 2539 households by the Ypartnership/Harrison group.
DELUXE IN DEMAND
Nudists also appear to be seeking out a higher-end experience far removed from the more affordable rustic tent camping and family-oriented sing-alongs by the campfire of previous generations, experts say.
"Wanting to be able to have a cocktail, wanting to be able to join a petanque team or play tennis competitively, or something like that, there is a trend of people looking for more upscale resorts," Weaver said.
Increasingly, those options are more available.
One of the more popular resorts, Cypress Cove, run by a third generation nudist family in Florida, has a pool, a 50-acre freshwater lake with paddleboats and canoes and six tennis courts, as well as a children's playground.
Another resort, Mira Vista, is offering premium condominiums for sale in Arizona complete with granite countertops and stainless steel appliances.
The two-bedroom condos, a step up from the mobile homes offered at several other resorts, start at $US199,000. So far, 17 units have been built and half of those sold. Some 115 units are planned, said Suzanne Schell, co-owner of Mira Vista.
The owner of another nudist resort, DeAnza Springs Resort in Southern California, said he had bought much of the tiny town of Jacumba on whose outskirts his resort sits and was in the process of renovating the hot springs and facilities there.
Owner Dave Landman said he did not want to turn the town into a nudist colony, but possibly an artists' community that nudists would see as friendly.
On cruises and at nudist resorts, where a strict code of conduct applies, owners occasionally have to deal with guests who came with faulty expectations, although several said that this was an increasingly rare experience.
Overt sexual activity is barred at resorts that fall under the American Association for Nude Recreation's banner, and sexualized clothing or accessories are not considered appropriate.
Visitors are typically advised to sit on towels to avoid sitting naked on furniture.
As for the next nude travel frontier, there is no shortage of ideas for vacations nudists describe as a significant source of stress relief for them as they leave societal norms and expectations behind.
Weaver said she would like to see nude golf, while another nudist dreamed of a nude town, where residents could go to the bank, grocery store or post office -- all in the buff.
But the bravest new adventure that Bare Necessities is considering is a naked cruise to an unlikely destination: Antarctica.
"We are looking at ships right now," Tiemann said, adding that her company had already successfully offered a naked cruise to Alaska. "Probably in the next two years we'll be announcing it."