The period has been subdivided into three main phases the names of which are derived from the sites where the cultural development characteristic of the particular phase has been recognized.

Early Cycladic I (Grotta-Pelos phase) 3200-2800 B.C. This phase is still close to neolithic tradition with evidently small settlements and cemeteries with cist graves. Burnished and incised pottery is the norm, the basic shapes being the crater and the pyxis. Marble vessels and figurines are especially characteristic. The chief marble vessels are the collared and footed jar ("kandila") and the beaker. The most popular form of figurine is the "violin-shaped", but there is also the more naturalistic "Plastira" type.

Early Cycladic II (Keros-Syros phase) 2800-2300 B.C. A rapid social and technical development is evidenced by the evolution of metallurgy, with an abundant production of tools and weapons , and of ship building and shipping with manoeurable, oared ships, thus opening lines of communication and trade in the Aegean. The settlements increase and develop ,becoming organized along urban lines. By the end of the phase they are fortified. The cemeteries, with cist graves and built graves, likewise increase in size. In addition to burnished pottery with incised and impressed decoration , painted pottery now appears and vases in new shapes such as the "sauce boat", the jug and "frying pan" . In marble, the bowl and the footed cup predominate , and the new type of marble figurine , the upright female figure with folded arms , becomes the hallmark of the phase and expands throughout the Aegean. The rendering of this figure as a lifesize statue, moreover ,initiates the appearence of large scale sculpture in the Aegean; this is the great achievement of the phase in this field. There is much communication with the northeastern Aegean , ties which are re-established at the end of the period.

Early Cycladic III (Phylacopi I phase) 2300-2000 B.C. Development of the settlements and predominance of pottery with painted dark coloured geometric decoration on a light ground. Marble figurines are restricted to a schematised conical form with projections at shoulder height. Tombs are rock cut.