The calculated distance (air line) between Saint-Sébastien-sur-Loire and Bordeaux is approximately 169 miles respectively 273 kilometers.
By car or train, the actual journey to Bordeaux is certainly longer, as only the direct route (as the crow flies) between Saint-Sébastien-sur-Loire and Bordeaux has been calculated here.
Air line (approximately)
273 kilometers
147 nautical miles