The calculated distance (air line) between Aix-en-Provence and Marseille 09 is approximately 19 miles respectively 31 kilometers.
By car or train, the actual journey to Marseille 09 is certainly longer, as only the direct route (as the crow flies) between Aix-en-Provence and Marseille 09 has been calculated here.
Air line (approximately)
31 kilometers
17 nautical miles