Based on untapped shipping and urban data, this article compares the diffusion of steam and container shipping at the port city level and at the global scale between 1880 and 2008. A temporal and multi-layered network is constructed, including the pre-existing technologies of sailing and breakbulk. The goal is to check the differences a) between innovations and their predecessors and b) between innovations, from an urban network perspective. Main results show that despite certain differences, such as historical context, voyage length, speed of diffusion, and geographical spread, the two innovations share a large quantity of similarities. They both fostered port concentration, were boosted by city size and port connectivity, bypassed upstream port sites, and diverged gradually from older technologies. This research thus contributes to the literature on cities, networks, innovation, and maritime transport.