The calculated distance (air line) between Arrasate / Mondragón and Galdakao is approximately 21 miles respectively 34 kilometers.
By car or train, the actual journey to Galdakao is certainly longer, as only the direct route (as the crow flies) between Arrasate / Mondragón and Galdakao has been calculated here.
Air line (approximately)
34 kilometers
18 nautical miles