« Fluvio-maritime » ships are specialist coasters whose size is suitable for navigating inland waterways. They provide services linking a sea port, two inland ports or sea and inland ports separated by sea without load breaking. Typically, « fluvio-maritime » services serve the British Isles or the Iberian peninsula from the Seine valley and the Paris region or the Mediterranean from the Rhone river ports.

In 2008, 1.3 million tonnes of goods were transported in France by these units from the two great basins of the Seine and the Rhone. This mainly concerns cereals, steel and heavy or bulky items.

Significant developments are expected for these services.