The calculated distance (air line) between Mechelen-aan-de-Maas and Sint-Niklaas is approximately 69 miles respectively 110 kilometers.
By car or train, the actual journey to Sint-Niklaas is certainly longer, as only the direct route (as the crow flies) between Mechelen-aan-de-Maas and Sint-Niklaas has been calculated here.
Air line (approximately)
110 kilometers
60 nautical miles