The Centers for Disease Control and Prevention (CDC) reported a norovirus outbreak on the Ruby Princess during its June 12 to July 2 Alaska voyage originating in San Francisco, California. This is the third CDC-reported norovirus outbreak on a Princess Cruises ship in 2026, more than any other cruise line.

The CDC first reported the outbreak on July 1, 2026. It states that 102 passengers and 23 crew members have reported being ill during the voyage and that the causative agent is norovirus. Norovirus is the most common gastrointestinal illness (GI) on cruise ships, accounting for 17 of 23 outbreaks in 2025.

The total number of sick passengers and crew may increase as the ship returns to port in San Francisco on July 2.

Earlier in May, the Caribbean Princess was hit with a norovirus outbreak that sickened 160 people. In March, 193 people were sick with norovirus on the Star Princess. This brings the total number of sick passengers and crew on Princess Cruises ships this year to 478. The only other cruise line with more than one GI outbreak is Lindblad Expeditions, which had two norovirus outbreaks in one month on its National Geographic Sea Bird.

Norovirus is highly contagious and can survive on surfaces for days or weeks, according to the CDC. The virus is typically spread through contaminated surfaces or food, making the communal spaces and buffet areas on cruise ships hotspots for the virus to spread. Symptoms of norovirus typically include diarrhea and vomiting. The virus is rarely deadly, especially for anyone healthy enough to cruise.

In response to the outbreak, the Ruby Princess‘ crew reported increasing cleaning and disinfection procedures, isolating ill passengers and crew members, and consulting with the CDC’s Vessel Sanitation Program (VSP).

The CDC reports GI outbreaks when 3% or more of a cruise ship’s passengers or crew members report having GI symptoms to the ship’s medical staff. Currently, 3.4% of passengers on the Ruby Princess have reported being sick.

This outbreak brings the total number of CDC-reported cruise ship GI outbreaks in 2026 to seven.

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