Legionnaires disease is a serious pneumonia caused by Legionella bacteria. Hot tubs can be a source of Legionella growth and transmission when they are inadequately maintained and operated. Private hot tubs on cruise ships are not subject to the same maintenance requirements as are public hot tubs in common areas. Lee S, Edens C, Ritter T, et al. Two Outbreaks of Legionnaires Disease Associated with Outdoor Hot Tubs for Private Use — Two Cruise Ships, November 2022–July 2024. MMWR Morb Mortal Wkly Rep 2024;73:950–954. DOI: http://dx.doi.org/10.15585/mmwr.mm7342a3