This article is the first-ever analysis of cities in relation to maritime transport flows from a relational, or network, perspective. Based on untapped vessel movement data covering the last 120 years, this articles sheds new light about the interdependencies at stake between urban hierarchies and port hierarchies overtime. Main results point to the fading correlation between traffic volume, port centrality, and city size, while the largest cities have maintained their prominence in the global maritime network despite contemporary spatial and functional changes affecting the distribution of transport systems and commodity chains. Such findings help better understanding not only the spatial and functional evolution of port-city relationships and maritime transport; they also confirm the importance of taking into account the long-term dynamics and socio-economic embedding of spatial networks in geography and other disciplines.