The complexity of port terminal operations and intermodal transshipments has pushed the introduction of information and communication technologies (ICT) to assist the multiple stakeholders involved in the multiple decision-making processes. More recently the development of systems based on the Internet of Things (IoT) represents a further step in the automation of data acquisition and processing. We present here an IoT system designed to optimize, manage and monitor container transport operations along an intermodal corridor, combining rail scheduling and inland vessel navigation. The system has a modular design, enabling the interaction with external systems, independently of their nature, through the cloud-based FIWARE platform. We provide a description of the three inter-related subsystems (container tracking, rail management and inland navigation), and a description of the expected supply chain benefits derived from the implementation of the system, both in terms of shippers and of terminal integration in the logistics flow. This system is currently operative at the Port of Seville, the main transshipment node in the Madrid – Seville – Canary Islands intermodal corridor in Spain.