From Brussels Airport (Zaventem)
It is situated to the North of Waterloo, approximately 20 minutes away by car. Take the motorway (Ring road) towards Charlerloi/Mons/Namur.
There is also a train:
There is train once per hour from Brussels Airport to Waterloo (trip duration: 45 minutes) and to Braine-l’Alleud (trip duration: 51 minutes).
(infrastructures, flight timetables, access plan from the airport)
From Brussels south airport (Charleroi)
It is situated to the South of Waterloo, approximately 45 minutes away by car. Take the A54 motorway towards Nivelles/Charleroi/Brussels.
There is a bus (twice per hour) that goes to Charleroi South station. From there you can take a bus (see section: “Bus 365”) or by train.