The calculated distance (air line) between Néa Chalkidóna and Sykiés is approximately 186 miles respectively 299 kilometers.
By car or train, the actual journey to Sykiés is certainly longer, as only the direct route (as the crow flies) between Néa Chalkidóna and Sykiés has been calculated here.
Air line (approximately)
299 kilometers
161 nautical miles