If you want to come to Liege to visit your housing options in person, you can book temporary housing for a few days or a few weeks.
More and more owners propose their housing for short-term as well. In the search filters, pick "daily" or "weekly" for the rental duration.
Liege Youth hostel is located in Outremeuse, a vibrant neighborhood 10 minute away from the city center by foot. Prices are reasonnable. Attention, it is often fully booked at the beginning of the semester.
Temporary housing is possible at the University residences. Location is a little away from the city center. It is located at the entrance of the University domain, in Sart-Tilman. It is a 25 minute ride away from the city center. It is a great choice if you are looking for housing close to the University location of Sart-Tilman. Not so much if you area looking for housing in the center. Prices are inexpensive.
The bigger private residences sometimes also offer temporary housing. Most are located in the center of Liege. Prices might be a little more expensive.