The calculated distance (air line) between Elefsína and Néa Smýrni is approximately 11 miles respectively 18 kilometers.
By car or train, the actual journey to Néa Smýrni is certainly longer, as only the direct route (as the crow flies) between Elefsína and Néa Smýrni has been calculated here.
Air line (approximately)
18 kilometers
10 nautical miles