Travelling from most locations, it is best to book your flight to Brussels during the month of March for the best deal, although there are other times of the year which offer great deals as well.
In general, most flyers find the cheapest time to book a flight to Brussels is about 59 days prior.
In general, booking your departure to Brussels for a Monday represents the best deal on airfare. Try to avoid a Friday departure to stay away from the highest prices.
Typically, cheap prices to Brussels are most often found for evening flights. Cheap prices are less likely for noon flights.