The calculated distance (air line) between Néa Erythraía and Korydallós is approximately 12 miles respectively 19 kilometers.
By car or train, the actual journey to Korydallós is certainly longer, as only the direct route (as the crow flies) between Néa Erythraía and Korydallós has been calculated here.
Air line (approximately)
19 kilometers
11 nautical miles