The A621 (Greek: Αυτοκινητόδρομος 621) is a short motorway in the Athens metropolitan area, Greece. It forms a connection between the northern beltway the A6 (Attiki Odos) and the eastern beltway A64 (Hymettus Peripheral Road).[1] Its length is 2 km.
On 4 December 2015, the Greek government proposed to renumber the A642 as the A621:[2] In practice, the renumbering had not taken place until 2024, because road signs were still showing the motorway as the A642. As of July 2024, the renumbering is being implemented due to road sign maintenance.
Source: Attiki Odos,[3] Motorway Exitlists[1]