If you land at Charleroi-Brussels South Airport (via Ryanair):
When you arrive at Charleroi-Brussels South Airport (http://www.charleroi-airport.com):
- Take the Bus A (number 68) to Charleroi main train station (called Charleroi-Sud).
- Get on the train to Mons. The journey lasts half an hour, and you need to take the IC train that goes to Tournai or Lille (it runs once an hour, for schedule check http://www.sncb.be).
- At the airport, don't take the bulk ticket that combines bus and train to any belgian station, it would be more expensive because the journey to Mons is short.
- You can buy bus tickets once on the vehicle, and train tickets in the station's main hall.