The calculated distance (air line) between Néa Kallikráteia and Glyfáda is approximately 173 miles respectively 279 kilometers.
By car or train, the actual journey to Glyfáda is certainly longer, as only the direct route (as the crow flies) between Néa Kallikráteia and Glyfáda has been calculated here.
Air line (approximately)
279 kilometers
151 nautical miles