Maritime transport is the backbone of global trade, a component driving globalization. Over 80 % of world trade in volume terms and over 70 % in value terms is done by sea; these proportions are even higher in most developing countries. This unceasing growth in maritime trade raises important questions concerning the development of ports role in worldwide transport. In recent years, container shipping has resulted in a specific network connecting the main ports together and these ports to smaller ones by regular feeder services which tend to use smaller size containerships. The development of the port system is concentrated in large ports, which attract considerable container traffic. This paper aims to present a survey of the current situation of container shipping in the Spanish ports which, comparing to north western European ports, have quite small markets and limited hinterlands that by consequences reduce attractiveness of ports. It focuses on the integration of ports in the containerization networks and on the organization of regular lines. The research was carried out using mainly Automatic Identification Data (AIS). The data acquired from AIS systems constitute a new means of information which allows to perform multiscale, diachronic and synchronic analyses. A desktop study as well as a statistical analysis which has required the construction of a database are also used. By focusing on vessels, shipping companies and ports, this communication considers the process of containerization in Spanish ports with a special attention on ports' network.