There are relatively few coastal Mesolithic sites in the Iberian Mediterranean region, probably due to a number of factors including sea level changes and the disappearance of sites due to agriculture and urbanisation. However, recent excavations have uncovered inland sites that have marine faunal remains (i.e. molluscs and fish) and lithics from the coastal area, which both indicate interactions between the coast and the upland valleys. These inland sites are located at a distance of 30e50 km from today¿s coastline and are at altitudes higher than 1000 m. We report on additional information on the links between the coast and these inland sites through the use of dietary isotope analysis (carbon and nitrogen stable isotope analysis) of collagen extracted from human and faunal remains at the sites of Coves de Santa Maira, Penya del Comptador and Cingle del Mas Nou. The results indicate that Mesolithic diet in this region was largely based on C3 terrestrial resources, but there was measurable evidence of low-level consumption of marine resources at both coastal and inland sites.