The Sele river plain is located along the western Tyrrhenian margin of the southern Apennine Chain and is confined seaward by a straight sandy coast formed during the Last Interglacial and the Holocene. The coastal plain is characterised by beach-dune ridges which interfinger landwards with lagoon and fluvio-palustrine deposits. This belt, which progressively grew up, represents the evolution of a barrier–lagoon system alternatively shifting landwards and seawards. The knowledge on the Holocene evolution of the Sele river coastal plain, along the coast of the Poseidonia-Paestum archaeological area, was improved by the drilling of two new cores and the collection of several archaeo-tephro-stratigraphic data. The area experienced the Holocene marine transgression which cut high cliffs in the travertine deposits. During the second half of the Holocene, the shoreline shifted seawards and a lagoon–beach bar system (Fossa Lupata-Laura) formed. The archaeological remains (VI cent. B.C.) and the Agnano Monte Spina tephra layer (4.1 ky BP) constrain chronologically this morpho-sedimentary system. After the VI cent. B.C., and mostly after the deposition of the 79 A.D. tephra layer, the shoreline shifted seawards and an additional beach ridge formed, while the flat area at the back (Fossa Lupata) was rapidly aggraded and dried up.