Historians have generally argued that between the medieval period and the eighteenth century seafarers transformed from collaborative adventurers with a share in their vessel to the first international wage‐earning proletariat. This interpretation has drawn upon relatively limited statistical analysis of mariners’ wages, and underestimates the variety of seafarers’ remuneration and economic activities besides wages themselves. This article undertakes a more sustained analysis of seventeenth‐century wage data drawn from the papers of the English High Court of Admiralty, and uses the same evidence to examine other forms of income, both customary payments as part of shipping, and small‐scale trade. Seafarers of all ranks carried their own commodities on all shipping routes, offering an opportunity to increase their income considerably. This evidence confirms that the maritime labour market was hierarchical, and that very often seafarers were poor labourers facing economic insecurity of many kinds. However, it refines the previous interpretation by emphasizing the presence of skilled workers even among the lower levels of this labour market, and by introducing a new dimension to mariners’ economic agency: they were not simply wage‐workers, but also independent participants in a venture economy.