The calculated distance (air line) between Bonn and Katwijk aan den Rijn is approximately 153 miles respectively 246 kilometers.
By car or train, the actual journey to Katwijk aan den Rijn is certainly longer, as only the direct route (as the crow flies) between Bonn and Katwijk aan den Rijn has been calculated here.
Air line (approximately)
246 kilometers
133 nautical miles