We present evidence of Middle Pleistocene activity in the central Aegean Basin at the chert extraction and reduction complex of Stelida (Naxos, Greece). Luminescence dating places ~9000 artifacts in a stratigraphic sequence from ~13 to 200 thousand years ago (ka ago). These artifacts include Mousterian products, which arguably provide first evidence for Neanderthals in the region. This dated material attests to a much earlier history of regional exploration than previously believed, opening the possibility of alternative routes into Southeast Europe from Anatolia (and Africa) for (i) hominins, potentially during sea level lowstands (e.g., Marine Isotope Stage 8) permitting terrestrial crossings across the Aegean, and (ii)
Homo sapiensof the Early Upper Paleolithic (Aurignacian), conceivably by sea.