This story has been updated.

The Treasury Department released several rules Tuesday restricting travel to Cuba. The most dramatic changes are the elimination of cruise visits and people-to-people trips. But while the U.S. government has closed some windows, the door to Cuba remains open a crack.

“We are really committed to continuing trips to Cuba,” said Peggy Goldman, founder and president of Friendly Planet Travel, which offers three itineraries to the Caribbean island. “This not the kiss of death for Cuba.”

According to the Office of Foreign Assets Control, which issued the restrictions, travelers who have made any transactions related to their trips to Cuba — such as booking flights, hotels or tours — before June 5 can proceed with their plans. However, the Commerce Department removed cruising from that grandfathered group. Effective Wednesday, the agency’s Bureau of Industry and Security stated, “private and corporate aircraft, cruise ships, sailboats, fishing boats, and other similar aircraft and vessels generally will be prohibited from going to Cuba.”

John McAuliff, executive director of the Fund for Reconciliation and Development, a nonprofit organization that helps foster connections between the two countries, summed it up as, “Cruises are dead in the water. They’re over.”

Added Goldman, “This ruling was intended to stop mass tourism, mainly by the cruises.”

The Cruise Lines International Association said the ruling will disrupt the vacations of 800,000 passengers, including cruisers aboard ships that are already underway. Nearly 143,000 Americans set sail to Cuba in the first four months of this year.

“We are disappointed that cruises will no longer be operating to Cuba,” said Adam Goldstein, CLIA’s chairman. “While out of our control, we are genuinely sorry for all cruise line guests who were looking forward to their previously booked itineraries to Cuba.”

Cruise lines are nimble and can quickly rearrange itineraries to avoid certain destinations. For example, ships add and subtract ports when a hurricane is hurtling toward the region or a collection of islands is recovering from a natural disaster. Cruise lines are scrambling to cut Cuba and plug the hole with another sunny spot.

Guests currently aboard Carnival Sensation’s June 3 sailing will be calling on Cozumel on Thursday instead of Havana. Guests will receive a $100 shipboard credit for the inconvenience. The cruise line is also notifying future passengers of their new Cuba-free itineraries. Travelers who stick with the same cruise will earn a $100 credit; those who switch to another itinerary will receive a $50 credit. The company is also offering a full refund to passengers who prefer to cancel.

“We are working as quickly as possible to secure alternative itineraries for the remainder of our Cuba voyages and expect to have information for sailings further out in the next two to three days,” Carnival said in a statement.

Royal Caribbean Cruises, parent company of Royal Caribbean, Celebrity Cruises, Azamara and Silversea, among other brands, said that 2019 sailings on the Majesty of the Seas and Empress of the Seas will swap out Cuba for such alternatives as Key West, Nassau, Mexico’s Costa Maya or Perfect Day at CocoCay in the Bahamas. Guests can cancel for a full refund or keep their reservation and receive a 50 percent refund.

Norwegian Cruise Line, which includes Regent Seven Seas Cruises and Oceania, said it will reach out to customers about modifications to their cruises. Viking Ocean Cruises has one Cuba cruise remaining this year. The company is assessing its options for that December trip as well as for its early 2020 sailings.

Unless the cruise line cancels the trip, passengers who purchased travel insurance will have little recourse.

“A change in cruise or tour group itinerary is not a covered reason to cancel a trip under a travel insurance policy,” said Jenna Hummer, a spokesperson for Squaremouth, which compares travel insurance policies. “As long as the ship or tour is scheduled to move forward with the voyage, travel insurance will not cover a traveler to cancel their trip.”

The rule also put the kibosh on people-to-people trips, the Obama administration program that encouraged Americans to interact with locals. Yet it preserved the similar Support for the Cuban People category. This means Americans can visit the island as long as they don’t frequent state-run businesses and institutions, such as hotels and restaurants. Instead, they must stay at private residences, eat in private restaurants, visit independently owned shops and devote their time to engaging with Cubans through such activities as volunteering in community projects.

Goldman said her company was already moving in that direction. She uses an independent bus company, not one owned by the Cuban army; taxis operated by private individuals; and guides who are historians, with the money going toward the rehabilitation of Havana’s buildings. Guests bunk in private homes called casa particulares and dine in private restaurants, or paladares.

“We will comb through all of our tours to comply with the other licenses,” she said. “It’s really not difficult for us to shift over.”

Tom Popper, president of InsightCuba, a travel company that leads tours of the island, said travelers who booked trips before the deadline will not see any changes to their itineraries. For future tours, his team will tweak certain elements to include private accommodations and excursions that comply with the law.

“The rule only went so far as to include these two categories,” he said. “It could have been a lot worse.”

Individuals, families and groups of friends can also travel under the aegis of the Support for the Cuban People category, as long as they abide by the guidelines and keep a record of their engagement activities for five years, McAuliff said. For example, the category requires U.S. visitors to follow a full-time schedule of experiences that “enhance contact with the Cuban people, support civil society in Cuba, or promote the Cuban people’s independence from Cuban authorities, and result in meaningful interaction with individuals in Cuba.”

“It’s very unclear what these activities are,” McAuliff said, “but they are consistent with independent travelers.”

The order for what is not permitted is less ambiguous: No substantial free time or recreation allowed.

Airlines, meanwhile, survived without a scratch.

“The regulations don’t directly impact them,” Popper said. “Cuban Americans sustain the number of departures, the size of the aircraft and the routes.”

However, McAuliff said the law could affect routes carrying passengers that are equally divided between leisure travelers and Cuban Americans visiting family. He said JetBlue could reconsider its flight from New York’s John F. Kennedy International Airport to Havana. Alternately, United’s Newark flight is probably safe because of the sizable Cuban American population in New Jersey, as are the many flights departing from Florida.

Of course, these rules could be a temporary obstacle to less-restricted travel to Cuba. McAuliff said Congress is expected to consider a bill that will end all travel restrictions, and it has garnered support from a bipartisan majority.

“The question is whether [President] Trump will veto it,” he said.

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