The calculated distance (air line) between Areaks Tnaot and Siem Reap is approximately 138 miles respectively 222 kilometers.
By car or train, the actual journey to Siem Reap is certainly longer, as only the direct route (as the crow flies) between Areaks Tnaot and Siem Reap has been calculated here.
Air line (approximately)
222 kilometers
120 nautical miles