The calculated distance (air line) between Phnom Penh and Krong Kep is approximately 85 miles respectively 137 kilometers.
By car or train, the actual journey to Krong Kep is certainly longer, as only the direct route (as the crow flies) between Phnom Penh and Krong Kep has been calculated here.
Air line (approximately)
137 kilometers
74 nautical miles