On July 4, more than 130 people onboard a week-long Royal Caribbean cruise reported suffering from a gastrointestinal disease, making up 3.4 percent of the ship’s total passenger list.

When the ship returned to Los Angeles July 11 after venturing around Mexico, both passengers and crew members revealed grisly symptoms. The cause of this specific outbreak on the cruise line’s Navigator of the Seas remains unknown.

Unfortunately, this isn’t an uncommon occurrence on cruise ships. This past April, an estimated 250 passengers on Cunard’s Queen Mary 2 reported having the contagious norovirus.

According to the CDC, in 2025 alone, there have been 18 disease outbreaks on cruise ships. From Silversea Cruises to Holland America Line to Princess Cruises to Viking, disease spares no brand when it comes to an outbreak. Most of these were identified as norovirus, but four outbreaks of the 18 remain unknown: Royal Caribbean’s Navigator of the Seas (July 4–11), Regent Seven Seas Cruises’ Seven Seas Explorer (April 26–May 14), Holland America Line’s Zuiderdam (Jan. 1–May 9) and Lindblad Expeditions’ National Geographic Sea Lion (April 15–29).

Other disease outbreaks in 2025 were attributed to E. coli and presumed Ciguatera.

These outbreaks can make travelers nervous about suffering a similar fate on an upcoming cruise. To a degree, it’s hard to completely avoid catching a contagious disease once it spreads on a ship. This is because, according to the CDC, “travelers from diverse regions brought together in the often crowded, semi-enclosed shipboard environment can facilitate person-to-person (contact, droplet, or airborne), foodborne, and waterborne transmission of communicable diseases. Outbreaks on ships can be sustained over multiple voyages by crewmembers who remain onboard or by persistent environmental contamination. Port visits can also expose travelers to local diseases and, conversely, can be a conduit for disease introduction into shoreside communities.”

And when a disease does emerge on a ship, medical facilities on the ship are typically limited, particularly when enough passengers come down with the illness.

In the event of outbreaks, especially with norovirus, the CDC lists responses cruise lines took to combat the illness, including increased cleaning and disinfection procedures, the cruise lines’ outbreak prevention and response plan, isolating ill passengers and crew, collecting stool specimens from gastrointestinal illness cases for testing, and consulting with CDC’s Vessel Sanitation Program about sanitation cleaning procedures and reporting ill cases.

It’s par for the course when bringing many people together in a confined space, but the CDC and cruise lines across the world continue to work to reduce outbreaks.

Have you ever been on a ship when an outbreak occurred? Email us at letters@globaltravelerusa.com. Please include your full name and location.