Please be aware that Brussels has multiple airports and that these results are for all airports serving the city.
The best month to fly between Brussels and Lisbon is January and the most expensive month to fly is April. (Average prices, based on 505 datapoints.)
The best day to arrive at Brussels is Wednesday and it would be best to avoid Friday, as prices are on average 41.68% higher than on Wednesday. (Average prices, based on 481 datapoints.)
The cheapest airline flying from Brussels to Lisbon is Ryanair. They are 56% cheaper than Brussels Airlines. (Average prices, based on 510 datapoints.)
The best time to fly is at around 16. (Average prices, based on 897 datapoints.)