The global cruise industry is lining up to get a bigger slice of the growing Chinese tourist pie, with Beijing putting its heft behind the expansion efforts just as growth in the U.S. market is slowing.
"Nearly all cabins of each cruise are sold out" in China, Carnival Corp., the world's largest cruise operator, said via email.
Read More Hey big spenders! Chinese travelers spend over $1,000 a day
The company is preparing to add a third Costa-branded ship to the Chinese market next year, chasing a market that may grow to nearly $10 billion in cruise package sales by 2018 from around $6.8 billion in 2013, according to data from Euromonitor. It's a big jump for a market that didn't have ports capable of supporting cruise ships until early this century.
Carnival's increased investment in China comes amid slowing growth in the North American cruise market, with the number of North American passengers rising just 1.2 percent in 2013 from the previous year, according to data from Statista.
Read More Chinese tourists to double by 2020: CLSA
So far, North America is easily the largest cruise market, with around 60 percent of forecast 21.6 million passengers expected this year globally originating there and an estimated annual revenue of more than $20 billion, contrasting with Asia's less than 7 percent of total passengers, according to data from Cruise Market Watch.
But China's people are developing ever-itchier feet. A CLSA report in January estimated that the number of mainlanders expected to travel abroad may hit 200 million a year by 2020, double 2013's level. Chinese travelers shelled out around $129 billion in 2013, according to data from the United Nations.
Carnival is tweaking its offerings to take a slice of that spending. On its Costa-branded ships, it's made obvious changes such as language and offering Asian foods to go with its Italian offerings, Arnold Donald, CEO of Carnival, told CNBC last week.
Read More China tourism boom is 'tip of the iceberg': Hotels.com
On its premium Princess line, its offerings now include Tai Chi classes, he said.
"They've also increased their retail luxury brands available because the Chinese have a real appetite for luxury brand shopping," he said.
Another draw for Chinese travelers may be onboard casinos. In 2013, more than a million trips were made by passenger vessels to Macau, as the enclave is the only place within China where gambling isn't outlawed, according to data from Euromonitor.
Carnival has also had to shorten the length of its offerings to accommodate the shorter vacations on the mainland, Donald said. At the same time, Carnival expects its first global cruise offering from the mainland, running 86 days on a Costa ship, will be sold out.
Read More US hotels courting Chinese travelers with tea, lucky numbers
Although Carnival declined to provide the ticket price for the Costa offering, its Princess line offers a 94-day world cruise starting in Los Angeles from around $18,000.
China's cruise growth may get a big fillip from Beijing's commitment to supporting the industry.
"China's policy to encourage the cruise economy is part of its strategy to promote marine industry as well as tourism," Angela Yu, an analyst at IHS, said via email, noting that the policy calls for large infrastructure investments.
Early last year, Qingdao Port announced an 800 million yuan ($130 million) investment to add a third cruise berth, expected to come online this year.
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter
