The calculated distance (air line) between Donostia / San Sebastián and Elgoibar is approximately 23 miles respectively 37 kilometers.
By car or train, the actual journey to Elgoibar is certainly longer, as only the direct route (as the crow flies) between Donostia / San Sebastián and Elgoibar has been calculated here.
Air line (approximately)
37 kilometers
20 nautical miles