The present study aims to investigate the effects of applying circular and industrial symbiosis models within the maritime sector, with a focus on logistics and transport. The intention is to focus on location decisions and the reduction of emissions. The rationale underpinning this study is to integrate strategies that facilitate the reutilisation of waste as a secondary raw material. The paper will analyse and examine how such circular practices can promote the sustainability of port infrastructures. The present study investigates and compares circular economy and industrial symbiosis initiatives integrated in the activities of port systems. The investigation will concentrate on two ports, Trieste and Koper, given their geographic proximity, in order to identify the actions and decisions taken by the ports with regard to the relationship between territorial location, territorial development and the various collaborations between actors. It is anticipated that the implementation of circular initiatives will result in a reduction of emissions, an enhancement of the competitive advantages held by the two analysed ports, and the promotion of activities and strategies that are aimed at efficient traffic management in accordance with European sustainability standards.