The calculated distance (air line) between Umi and Maebaru-chūō is approximately 18 miles respectively 29 kilometers.
By car or train, the actual journey to Maebaru-chūō is certainly longer, as only the direct route (as the crow flies) between Umi and Maebaru-chūō has been calculated here.
Air line (approximately)
29 kilometers
15 nautical miles