If you've ever thought it would be fun to just stay on a beautiful ship for a week without bothering with ports, there's a legal reason that's not on the menu — at least not from any U.S. homeport. A law called the Passenger Vessel Services Act (PVSA) prohibits foreign-flagged vessels from transporting passengers between two U.S. ports without stopping at a foreign destination. Since a cruise that leaves Miami and returns to Miami without visiting any foreign port technically falls under this rule, it creates a violation. Fines under the PVSA reached nearly $1,000 per passenger as of November 2015.

For a while, cruise lines including Carnival and Norwegian quietly operated one- and two-night cruises to nowhere before 2016, and regulators largely looked the other way. That changed when Bimini Superfast — a Miami-based gambling cruise operator — tried to expand to Port Everglades in Fort Lauderdale. U.S. Customs and Border Protection intervened, pointing out a second legal wrinkle: most cruise ship crew members hold D-1 visas, which only permit them to work aboard vessels that visit foreign ports. Since cruises to nowhere never leave U.S. waters, those visa holders legally can't serve as crew. CBP filed and won a lawsuit to enforce the rule, and all major cruise lines had to fall in line.

Ships operating outside the U.S. face no such restrictions, which is why vessels like Disney Adventure, Anthem of the Seas, and Spectrum of the Seas offer cruises to nowhere from ports in Singapore, Sydney, and Hong Kong.

Even setting the legal issues aside, Royal Caribbean says destinations are central to why people cruise in the first place. Jay Schneider, Royal Caribbean Group's Chief Product Innovation Officer, has noted that guests cruise primarily to visit destinations and enjoy food. The line's private island, Perfect Day at CocoCay, exemplifies that philosophy — Royal Caribbean International President and CEO Michael Bayley has said the island welcomed roughly 3.5 million guests in a single year, making it the company's top demand destination globally.

Looking ahead, Royal Caribbean is developing its Discovery Class of smaller ships specifically designed to reach ports inaccessible to its massive Icon and Oasis Class vessels, with plans to sail to Asia, Alaska, and Europe — and the ability to transit the Panama Canal for faster repositioning. This article draws on reporting from Royal Caribbean Blog.