This research deploys an maritime and coastal approach, combining archeology and marine geosciences on the old “Baye de Bretagne” localised in Loire-Atlantique (France). In medieval and modern times, this bay was an important salt supply center for merchants and fishermen in Northern Europe, then a large anchorage linked to Nantes and to the maritime route between Saint-Malo, Lorient and La Rochelle. But, at the end of the medieval period, the evolution of the environment and the use of space conditions the reorganization of nautical and maritime activity. And now, what are the archaeological markers of this activity on land and under the sea ? And what can they teach us about the resilience of coastal populations ? The oceanic coastal societies of the past have succeeded in exploiting resources, creating port facilities and navigation techniques for their growth by seizing the coastline and adapting to changing constraints. They thus produced a “maritime cultural landscape”. The Land-Sea continuum has become a vast and complex maritime network with urban, port and artisanal areas interconnected with maritime routes. The challenge of this proposal is therefore to indentify the construction and evolution of the maritime landscape.