The calculated distance (air line) between Bochum-Hordel and Oostkamp is approximately 172 miles respectively 277 kilometers.
By car or train, the actual journey to Oostkamp is certainly longer, as only the direct route (as the crow flies) between Bochum-Hordel and Oostkamp has been calculated here.
Air line (approximately)
277 kilometers
149 nautical miles