The calculated distance (air line) between Khorramshahr and Umm Qaşr is approximately 32 miles respectively 52 kilometers.
By car or train, the actual journey to Umm Qaşr is certainly longer, as only the direct route (as the crow flies) between Khorramshahr and Umm Qaşr has been calculated here.
Air line (approximately)
52 kilometers
28 nautical miles