By train or bus

Train | NMBS

Leuven is easy to reach by train from all Belgian and European cities. The station is very close to the town centre. 
Leuven is a 20-minute train ride from Brussels, 50 minutes from Antwerp, 30 minutes from Liège and 1.5 hours from the Belgian coast. 
Your train journey from Leuven to Brussels South Station takes just half an hour. If you take the Eurostar or the Thalys you can be in Paris in 1.5 hours and in London, Amsterdam or Cologne in 2.5 hours.

More info: website NMBS

Bus | De Lijn

The central departure point for the local buses is at the railway station. The buses that leave from here serve all the outlying areas and surrounding communes of Leuven.

More info: website De Lijn