Norwegian Cruise Line has finally restarted sailing after a 500-day suspension. All passengers on the 7-day Greek Isles cruise must be vaccinated and wear masks.

• The Norwegian Jade set sail from Athens, Greece, on Sunday for a seven-day Greek islands tour.
• It was the first of Norwegian's 17-ship fleet to restart sailing following a 500-day suspension.
• All passengers and crew have to be vaccinated and wear masks.
• See more stories on Insider's business page.

Norwegian Cruise Line has restarted sailing after a 500-day suspension during the pandemic.

The ship, the Norwegian Jade, set sail from Piraeus in Athens, Greece, on Sunday for a seven-day tour of the Greek islands.

Passengers can only board if they're vaccinated against COVID-19.

As well as being the first of Norwegian's 17-ship fleet to restart sailing, the Norwegian Jade also became the cruise company's first vessel to make Athens its home port.

Norwegian, one of the world's biggest cruise companies, announced in April that it would require the COVID-19 vaccine for its guests and crew. It even threatened to avoid all Florida stops after the state banned businesses from asking for proof of vaccination.

Passengers can go maskless on most of its cruises, though masks are still mandated for cruises in Europe, per local government regulations.

All guests are also required to take a COVID-19 antigen test, administered and paid for by the cruise line, before boarding.

The cruise takes passengers to islands including Crete, Mykonos, Rhodes, Corfu, and Santorini as part of its "Greek Isles" trip.

Read more: Norwegian Cruises' CEO is eyeing acquisitions thanks to an $8 billion war chest raised during the pandemic. Here are the 6 companies it could pick up, per experts

"Norwegian Jade's first Greek Isles voyages sold out shortly after we made the announcement that we were on our way back," Norwegian CEO Harry Sommer said in a press release.

The ship has 15 different restaurants and cafes, an art gallery, a casino, a library, and a video arcade.

After the debut journey, the cruises are departing each Sunday from August 29 through November 7.

Prices vary from about $677 per person for an inside cabin to more than $4,500 for "The Haven," which comes with 24-hour butler service and an exclusive sundeck with pool.

"People are champing at the bit to cruise again," the CEO of Carnival Corp, the world's biggest cruise company, told Fox Business in June. He said that people were confident in the safety of cruises as the vaccine rollout continued across the US, and that the shots were a "huge game-changer."

Norwegian said the Norwegian Jade's deployment in Athens is part of a long-term strategy to increase its presence in Europe. It plans to base nine ships in the region through 2023, it said.

Norwegian's first ship to return to service from the US will be the Norwegian Encore on August 7, which will start in Seattle for its inaugural season of Alaska cruises.