The calculated distance (air line) between Aix-en-Provence and Marseille 08 is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Marseille 08 is certainly longer, as only the direct route (as the crow flies) between Aix-en-Provence and Marseille 08 has been calculated here.
Air line (approximately)
29 kilometers
16 nautical miles