The calculated distance (air line) between Barajas de Madrid and San Sebastián de los Reyes is approximately 6 miles respectively 10 kilometers.
By car or train, the actual journey to San Sebastián de los Reyes is certainly longer, as only the direct route (as the crow flies) between Barajas de Madrid and San Sebastián de los Reyes has been calculated here.
Air line (approximately)
10 kilometers
5 nautical miles