The calculated distance (air line) between Sihanoukville and Kampong Cham is approximately 162 miles respectively 261 kilometers.
By car or train, the actual journey to Kampong Cham is certainly longer, as only the direct route (as the crow flies) between Sihanoukville and Kampong Cham has been calculated here.
Air line (approximately)
261 kilometers
141 nautical miles