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