Recent scholarship on seafarers in the late nineteenth and early twentieth century has tended to emphasise the mobility and diverse geographical origins of the global steamship workforce. This article, while sharing that perspective, cautions that a more nuanced view is called for, which also recognises the limits of their mobility. In doing so, it suggests, more broadly, that the period before the First World War cannot be thought of simply as an ‘Age of Acceleration’, but also needs to be seen as a period in which new kinds of limitation to mobility emerged. In the British colonial port of Durban, although there was in this period a vast increase in shipping activity, seamen were subject to an intense regime of restriction. An immigration bureaucracy initially created to exclude Indian immigrants, also shut out sailors of all nationalities and races. A particular precipitant of this policy was the hostility of Natal officials to the crews of ‘cattleboats’, ships bringing livestock to southern Africa from the Mediterranean, Argentina, Australia, the US and elsewhere. Across the globe, immigration controls in this period were in general less intense than they became after 1914, but in some places, such as Durban, new forms of limitation on mobility were being tried out. The article also highlights the vast worldwide system of labour documentation operated by the British merchant marine through Shipping Offices and Consuls in almost every significant port. Mobility in the British Empire was radically differentiated, with numerous centres of power making their own claims to control movement.