Two passengers on a Royal Caribbean (RCL) cruise have tested positive for COVID-19 during a sailing to The Bahamas.

The guests, both under the age of 16, were unvaccinated. One guest is experiencing mild symptoms, and the other is asymptomatic, according to Royal Caribbean. Both passengers were immediately quarantined.

The infections were discovered when the passengers tested positive for the virus during routine testing, which is required before returning home amid sailing. Those in the teens’ immediate travel party were vaccinated against the virus and tested negative for COVID-19.

It was not required for the passengers under the age of 16 to be on the cruise, which Royal Caribbean said 92% of guests onboard the ship were vaccinated. Crewmembers working the ship were 100% fully vaccinated, the cruise line said.

The remaining 8% of passengers that were not vaccinated on the cruise were under the age of 16. Royal Caribbean will require passengers aged 12 and up to be fully vaccinated to board its ships, starting on Aug. 12.

Close contacts to the infected passengers were also identified and tested. Royal Caribbean said they were all vaccinated and tested negative for COVID.

The passengers were both onboard the Adventures of the Seas ship that disembarked in Freeport, The Bahamas, where they, along with their travel party, disembarked and headed back home to Florida on Thursday.

The news of two passengers testing positive for COVID comes after another two passengers onboard its Celebrity Millennium cruise tested positive on a sailing to St. Maarten, and eight crewmembers tested positive on its Odyssey of the Seas ship, delaying its inaugural Caribbean cruise.

The cruise industry is just returning to U.S. waters this month after suspending operations for 15 months due to the pandemic. Cruise ships were seen as superspreaders sites and forced by the Centers for Disease Control and Prevention to shut down through a No Sail Order, which has been lifted with a series of guidelines in place, including a vaccination requirement except for cruises leaving Florida ports.

Shares of Royal Caribbean were trading at $87.19 as of premarket hours on Friday, up 22 cents, or 0.25%.

Dock workers tie the Royal Caribbean’s Odyssey of the Seas to its berthing spot on June 10, 2021 in Fort Lauderdale, Florida
Dockworkers tie the Royal Caribbean's Odyssey of the Seas to its berthing spot on June 10, 2021, in Fort Lauderdale, Florida. GETTY IMAGES NORTH AMERICA / JOE RAEDLE