The calculated distance (air line) between Néa Pentéli and Palaió Fáliro is approximately 13 miles respectively 20 kilometers.
By car or train, the actual journey to Palaió Fáliro is certainly longer, as only the direct route (as the crow flies) between Néa Pentéli and Palaió Fáliro has been calculated here.
Air line (approximately)
20 kilometers
11 nautical miles