Infected people usually experience acute onset of vomiting and non-bloody diarrhea. The incubation period is 12–48 hours. Other symptoms include abdominal cramps, nausea, and sometimes a low-grade fever. Illness is generally self-limited, and most patients fully recover in 1–3 days.

The incubation period for norovirus—the time between exposure to the virus and the first appearance of symptoms—is typically 12 to 48 hours. As of 2026, the CDC and health agencies emphasize that the onset is famously sudden; a person can go from feeling perfectly healthy to experiencing intense vomiting and diarrhea in a matter of hours. Symptoms generally last for 1 to 3 days in healthy adults but can be more severe in children and the elderly. A critical fact for 2026 travelers (especially on cruises) is that you remain contagious for at least 48 hours after your symptoms have completely disappeared. Because the virus is extremely hardy and resistant to many hand sanitizers, the "gold standard" for prevention remains vigorous handwashing with soap and water for at least 20 seconds after any potential exposure.