Cruise Ships Can Sail Again, With Strict Rules. Here’s What to Know.

The Centers for Disease Control and Prevention on Friday lifted its “no sail” order on U.S. cruise ships and set out a framework for how cruising could restart.

Under the new structure, cruise companies must demonstrate adherence to stringent health and safety protocols including extensive testing, quarantine measures and social distancing. If they meet these C.D.C. standards, first on a series of crew-only test sailings, they will eventually be allowed to resume passenger excursions.

The “no sail” order was originally issued on March 14 for all American cruises after it emerged that cruise ships played a major role in the initial outbreak of the coronavirus. The ships were remarkably efficient at spreading the virus: On board the Diamond Princess cruise ship in Japan in February, each case of Covid-19 was transmitted to approximately 15 other people. In Wuhan, China — the original epicenter of the virus — one person transmitted the disease to about four other people, a recent study published in the Journal of Travel Medicine found.

In September, the C.D.C. recommended an extension to the policy until February amid reports of outbreaks on ships in other countries, but that advice was overruled by a White House coronavirus task force.

The restrictions on sailings have ravaged the cruise industry with companies reporting billions of dollars in losses as their fleets have remained idled in open waters or in ports. In recent months, cruise executives have been scrambling to put together teams of scientists and health experts to devise comprehensive safety protocols that will allow cruising to return, and they gave a lengthy list of suggestions to the C.D.C.

On Friday, the C.D.C. said the benefits of the new framework outweigh the costs of not allowing cruise ships to sail, providing flexibility for companies that have taken necessary precautions to mitigate risk, while continuing to prohibit operations for those that fail to implement the necessary measures.

Here’s how the decision will likely impact cruises in the coming months.

How soon will I be able to get on a cruise?

In short, not soon.

The first ships to sail in U.S. waters will be simulated voyages designed to test a vessel’s capabilities to implement health and safety protocols and prove the cruise line’s ability to mitigate the risks of Covid-19 onboard.

Cruise lines will not be allowed to commence passenger operations until they meet all the requirements and are granted a conditional Covid-19 sailing certificate issued by the C.D.C.

Most major cruise lines have announced that they will not resume operations until 2021.

The largest cruise companies, including Carnival, Royal Caribbean and MSC have canceled their sailings through the end of November. Last month, Carnival canceled all its 2020 cruises, except for those between Miami and Port Canaveral, Fla., which are scheduled to restart in December.

What safety measures can I expect?

The ships will be required to provide rapid laboratory testing of all passengers and crew on the day of embarkation and the day of disembarkation. Onboard testing capabilities will be developed in coordination with the C.D.C. to test all symptomatic travelers, including crew members and future passengers.

Under the new order, cruise ship operators must meet standards for hand hygiene, face coverings and social distancing for passengers and crew as well as ship sanitation. Meal services and entertainment venues will be modified to ensure that physical distancing can be implemented.

Does that mean I’ll have to wear a mask?

For the test cruises, the C.D.C. said that masks are one of the measures that “may be required by C.D.C. technical instructions or orders,” but it does not lay out where and when they might be mandated. Mask use was included among the suggestions from the industry executives to the C.D.C.

What happens if I test positive for the coronavirus?

Passengers who test positive for Covid-19 before boarding a cruise ship will not be permitted to board. Those who test positive onboard a ship will be isolated and then transferred to a dedicated facility on shore. All remaining passengers and nonessential crew will also be required to go into quarantine. In the spring, some passengers spent weeks confined to their staterooms after cases broke out on board their cruises.

Cruise operators are expected to have the proper medical equipment, expertise and training to treat severely ill passengers who contract Covid-19 while on board until they can be safety transferred to onshore medical facilities.

Will passengers be allowed to go on shore excursions?

Initially shore excursions will be closely controlled and limited to private and domestic destinations. Cruise operators are devising protocols to vet vendors for onshore excursions to ensure that they comply with health and safety protocols that are applied on board ships. The measures include physical distancing, sanitation, personal protective equipment, personnel screening and training.

On a recent sailing by the Costa Diadema, a ship belonging to the Carnival Corporation’s Italian cruise operation, cases cropped up despite testing after passengers took shore excursions on the Greek Islands. The guests were asymptomatic and tested positive upon re-entry into Italy.

Under the C. D.C.’s new requirements, cruise ships will not be permitted to sail with an itinerary that lasts longer than seven days. This period may be shortened or lengthened based on public health considerations.

The health agency’s framework applies to cruise ships that intend to operate in U.S. waters.