The calculated distance (air line) between Saint-Laurent-de-la-Salanque and Marseille is approximately 126 miles respectively 203 kilometers.
By car or train, the actual journey to Marseille is certainly longer, as only the direct route (as the crow flies) between Saint-Laurent-de-la-Salanque and Marseille has been calculated here.
Air line (approximately)
203 kilometers
109 nautical miles