Popular coach line
BlaBlaBus are viable options. Check times and availability for BlaBlaBus, as it was recently the cheapest bus available travelling from Cologne Köln/Bonn to Brussels Bruxelles-National from £46 round-trip.
A bus from Cologne Köln/Bonn to Brussels Bruxelles-National will travel much more than the 107.5 mi distance between them. The actual distance depends on the route taken, which can change based on traffic, tolls and closures.