With its marina and its stunning bell tower, Marans is linked to La Rochelle by a waterway. Around, the green landscapes of the "dry marshland" which are characterized by large fields conquered from the sea and swamps thanks to the construction of drainage channels and hydraulic structures.

The Sèvre Niortaise, the vertebral column of the Marais Poitevin, crosses Marans and extends from the east of Niort to its estuary, Baie de l'Aiguillon, where it joins the ocean.