The calculated distance (air line) between Gernika-Lumo and Aretxabaleta is approximately 22 miles respectively 35 kilometers.
By car or train, the actual journey to Aretxabaleta is certainly longer, as only the direct route (as the crow flies) between Gernika-Lumo and Aretxabaleta has been calculated here.
Air line (approximately)
35 kilometers
19 nautical miles