To get to the CS department by public transport:

Coming from downtown is most likely best by metro, line 5, to Delta. This runs through the neighborhood of Etterbeek, serving the ``E.U. district". Bus 95 is a another option, and usually faster than bus 71.

The 71 runs through the Ixelles neighborhood that stretches from downtown to ULB, and the 95 runs on the border of Ixelles and Etterbeek. Take the 95 to "Thys" (1 stop before cimetiere d'ixelles), or the 71 to just outside campus (in between cim.ixelles and Delta). Bus 34 runs in the same direction, a bit further east of 95, within Etterbeek, reaching the other side of campus. To the west of the 71 is avenue Louise, with a few trams reaching reasonably (but not quite as) close to campus. Roughly, imagine five southbound parallel lines ordered from west to east: Louise, 71, 95, 34, metro -- all approaching to within 5-10 walking distance.

Arriving from outside of this Ixelles/Etterbeek region would typically involve a tram along Boulevard General Jacques, taking you to the north side of campus next to VUB.