In a world where most international trade is carried by sea, each port can be seen as a unique chokepoint competing to attract ever more traffic and economic activities. However, ports can also be seen as parts of a wider system, which can be defined as a system of two or more ports located in proximity within a given area. Their fate and governance is jointly influenced when belonging to the same region, country, or transnational space. Investments, shocks, innovations, and delays occurring in one port often affect other ports within a certain spatial range and time lapse. Further understanding of such co-developments in port systems is necessary to go beyond local specificities, through a multidisciplinary and multi-level contribution. …