From the 1870s a growing number of Indian seafarers went to work on foreign vessels, the large majority (over two thirds) on British ships. These sailors inhabited a world deeply marked by race which determined what they would do, how much they would be paid, and how they could be treated. Yet, until recently, Indian seafarers have languished as a historically invisible underclass. This paper contextualizes the development of the Indian sailors' recruitment and working conditions, and describes the campaigns organized by British trade unions against Asian crews.