From the mid-nineteenth century, seamen were increasingly identified as vectors of epidemic diseases such as cholera. The rising acceptance of the germ theories of disease and contagion and the transition from sail to steam at this time increased the fear of the rapid spread of contagious diseases through these mobile people. This article examines how the British naval authorities, ship surgeons and the medical and municipal authorities in the Calcutta sailortown sought to improve maritime health and hygiene to prevent the spread of cholera among and by British seamen. Nineteenth century Calcutta is an ideal context for this study on account of its epidemiological notoriety as a disease entrepot and the sea route between Calcutta and British ports was one of the most closely monitored for disease in the Empire. The article argues that a study of cholera among British seamen can generate important insights into the relationship among disease, medicine and colonialism and in doing so shed light into a neglected aspect of the history of nineteenth century cholera, the British anxiety regarding disease dispersion, practice of hygiene and sanitation and British seamen’s health.