Guests lined up to board Royal Caribbean Cruises Ltd.’s Freedom of the Seas on Sunday, marking the first cruise from a U.S. port since the pandemic suspended operations 15 months ago.

Passengers filed into PortMiami with suitcases in tow, a sight last seen in the world’s largest cruise port in March 2020. Freedom of the Seas can carry around 4,500 guests, and it’s expected to take about 650 on this first two-night loop, all of them Royal Caribbean employees who volunteered and were allowed to bring an 18-and-over guest.

“I feel really safe with my mask, I’m vaccinated, everyone’s vaccinated, so I feel really good about it,” said Carolina Jimenez, a 25-year-old law student who was invited along as a plus-one. “It’s unfortunate how long it’s taken to come back, but I think that’s something no one could have controlled, and I’m just glad that now we’re here and getting back to it.”

The trip is being dubbed a “simulated voyage,” a concept designed by the U.S. Centers for Disease Control and Prevention to essentially prove the ships are safe to sail with COVID-19 still around the globe.