Maritime transport in Spain is going through a crucial stage with the entry into force of the new environmental regulations promoted by the European Union, whose main objective is to tackle climate change and reduce greenhouse gas emissions. In this context, the incorporation of maritime transport into the Emissions Trading Scheme (ETS) marks an important milestone in the European decarbonization strategy. However, this step forward is not without significant challenges for a sector facing the need to adapt to a more demanding regulatory landscape and competition from non-EU ports.