This article investigates the uses of the discourse of the law of nature and nations on the Guinea Coast of West Africa in the mid-eighteenth century. Drawing on the archival material of the Danish West India-Guinea Company and other contemporary sources, the article shows how the law of nature and nations was a key discourse by which Europeans and Africans made claims against each other competing for trade and territories in the context of the Atlantic slave trade. It argues that it fulfilled this role for a number of reasons. It had become the chief European discourse for conceptualising rights, property, and jurisdiction, and which provided a standard putatively common to both Europe and the Guinea Coast. As such, it both validated the established ‘customs of the coast’ and at the same time inscribed Europeans and Africans on the Guinea Coast in a larger colonial intellectual, legal, and political order. In this, Africans were routinely described as subjects of the different European nations on the coast.