The calculated distance (air line) between Yên Bái and Dien Bien Phu is approximately 124 miles respectively 199 kilometers.
By car or train, the actual journey to Dien Bien Phu is certainly longer, as only the direct route (as the crow flies) between Yên Bái and Dien Bien Phu has been calculated here.
Air line (approximately)
199 kilometers
107 nautical miles