This article seeks to illustrate the decisive contribution of the sea environment and particularly the sea-surface circulation (which is determined by the circulation of sea currents and the winds) to the early growth of seafaring and maritime communications in the prehistoric Aegean. Given the means and techniques of navigation in that era, an attempt is made to reveal a dense network of sea routes which vessels could follow through the Aegean, in order to facilitate their trip. These sea routes are primarily based on environmental data and are confirmed concurrently by archaeological evidence and data of ancient sources. Therefore, it is evident that these sea routes played an important role not only in the early inhabitation of the Aegean islands and the foundation of coastal settlements throughout the Aegean area from the sixth millennium BC to the end of the third millennium BC, but in the development of the Aegean civilization during earlier prehistoric times as well.