If you are flexible with your travel dates, always consider that you can buy extremely cheap train tickets if you avoid travelling in the weekends and if you choose to travel during the low season.
Since the journey between Brussels and Liège is relatively short, you can consider carpooling or bus as alternative ways of transport with cheapest prices and similar duration.
Which stations serve the rail line Brussels - Liège?
The trains to Liège can leave from Bruxelles Central and arrive at Liege-Guillemins.
How long to you need to get to Liège by train?
The first train to Liège leaves at 06:08, whereas the last one at 18:08. On average, the journey lasts 59 minutes, but with the fastest connections you will be in Liège in 57 minutes.