The earliest phase of the defensive wall is dated to the reign of the Macedonian King Kassander. The fortified enceinte wsa of rectangular, almos square plan and the area into muros was approximately 43 hectares. The foundation of the wall followed the configuration of the ground, which sloped appreciably from west to east. Two or three coures of conglomerte stones from Olympus were laid upon the euthynteria. At 33-metre intervals stood a square tower (7x7m), incorporated in the wall. Additional defensive work, such as the moat, reinforced the protection of the city. On the east of the wall, where the Vaphyras flowed, there were very possibly riverine harbour installations. The early Hellenistic fortification of Dion was destroyed during the Aetolian invasion in 219 BC, but was reconstructed immediately after by Philipp V.

In Roman times the greater part of the brick-built upper structure of the wall collapsed. Indeed, part of the south side was demolished, in order to built the great baths there. The wall was repaired once more in th mid-3rd century AD, to protect the city from the incursions of barbarian tribes. In this phase the east side was shifted westwards, because of the displacements of the bed of River Vaphyras. The late Roman enceinte was 2,800 meters in perimeter and enclosed an area of 37 hectares. Earlier architectura members (spolia), funerary altars and fragment of sculptures of various periods were used as building material.