The Brussels metro is fast and covers the main tourist areas — the airport line, the north-south spine through the centre, and the east-west line through the Schuman/EU quarter. Trams fill in the gaps, particularly useful for getting between the Lower Town and Ixelles or Saint-Gilles. The MIVB/STIB network covers all three (metro, tram, bus); a day pass or multi-day ticket is the most convenient option for short stays.
Walking is by far the best way to explore the historic centre, the Sablon, the Royal District, and the inner communes. The distances are modest and many of the best things — Art Nouveau facades, hidden courtyards, the Galeries Saint-Hubert — only reveal themselves at street pace.
Taxis are plentiful but expensive by Belgian standards. The main taxi ranks are at the Bourse, the Grand-Place, and the main stations. Ride-hailing apps also operate.
The main train stations — Bruxelles-Midi/Brussel-Zuid, Bruxelles-Central, and Bruxelles-Nord — are all connected by metro and tram. For intercity travel to Bruges, Ghent, or Antwerp, trains run frequently from all three and take 30–60 minutes.