Maritime transport is the backbone of international trade. More than 80% of world trade by volume is carried by sea. Moreover, the continued growth of seaborne trade imposes a new environment on the development and role of ports in the global maritime system and supply chain. Major ports have established themselves as a fundamental element in maritime shipping, participating actively in the general movement towards the globalization of the economy. As a consequence, the largest maritime ports, with very large tonnages, lie at the heart of research questions. However, despite the process of port concentration, this system is also characterized by the permanence of small or medium-sized ports, often specialized, which perform more local functions and mainly serve smaller hinterlands. These small port entities are rarely studied by researchers. Yet many local ports have an important role to play in the economy and raise many relevant questions concerning, for example, territorial development, connectivity of maritime networks, or the strategies of actors. The activity of small seaports often varies from niche traffic to a small role in containerization. In this context, small container ports rely on feeder services to and from hub ports to provide access to unified trade flows to their hinterland. These smaller, mostly decentralized, ports, and/or managed more locally, constitute a resource pool of activity and employment for the local area. They open up possibilities for other transit networks and the implementation of logistics with lower carbon emissions. This article proposes to analyze the position of small ports in maritime transport networks. It aims to present the first results of a research on the situation of small ports in two different territorial configurations: the ports of the Adriatic Sea and the case of the Baltic Sea region. The first objective is to define what a small port is, especially by using a documentary study. Secondly, the research is carried out using mainly Automatic Identification System (AIS) data as a new and efficient source to perform multi-scale, diachronic and synchronous analyses and to study the integration of small ports in the maritime network. It makes it possible to determine precisely the place of the ports in the shipping lines’ networks, to quantify the shipping services offered in the seaports as well as the strategies of the shipping companies. For these reasons, AIS data and the methodology we use allow us to provide an original analysis of small ports.