Linguistic contact is possible at any time. Greek colonies provide a privileged viewpoint from which to regard this issue. In this paper, four cases are discussed on the basis of the dialectal material found in the Euboean colonies of Sicily and Magna Graecia: 1) features that can be ascribed to the originally mixed character of the colony’s population already at the time of the colonial enterprise; 2) features related to the presence of foreigners in the colony who arrived after its foundation, from faraway lands, or 3) from nearby regions, as in the case of the influence from other Greek colonial settlements or even from non-Greek settlements. A fourth possible case regards people coming from the mother-town at a later time after the foundation of the colony and bringing with them non-colonial features of the same alphabet and/or dialect.