20 km de Bruxelles.
With 47,253 starters from 141 nations, the 20 km de Bruxelles is by a distance the biggest running event in Belgium – and a course that saves its decision for the very end. After four kilometres of descent into the Woluwe valley, the Avenue de Tervueren rears up at kilometre 18 and takes another 37 metres of climbing out of you before you run in to the Parc du Cinquantenaire.
20 km de Bruxelles 2027: Course, Route Profile & Map
The start is on Avenue de la Joyeuse Entrée beside the Parc du Cinquantenaire, at a little over 70 metres. The opening kilometres fall towards the city centre and pass Place Poelaert below the Palace of Justice. From there the course tilts up between kilometres four and seven: Avenue Louise and on to the Bois de la Cambre, some 50 metres of climbing across three kilometres, spread so evenly that the profile does not even rate it as a climb.
Between kilometres seven and thirteen you stay up on the Solbosch and Boitsfort plateau, between 95 and 112 metres, in constant small undulations with one 300-metre ramp at kilometre 9.6. Then the course tips over. For four kilometres you run down into the Woluwe valley, from about 105 metres to the low point of 51 metres at kilometre 17.3 – free time, which you pay back immediately.
Because from kilometre 17.95 the Avenue de Tervueren rises: a dead-straight boulevard lined with old trees, a good kilometre at an average of 3.5 percent, 37 metres of climbing up to Montgomery. From there it runs gently downhill back under the triumphal arch into the Cinquantenaire. Since the first edition on 8 June 1980 – 4,659 starters, finishing at the Atomium – the race has grown into a city-wide party: six water points, 14 Red Cross tents, bands at the roadside and a field that sells out faster than the city can close the streets.
| Start | Length | Ø | Max. | Gain | Cat. |
|---|---|---|---|---|---|
| km 9.6 | 0.3 km | 3.4 % | 4.6 % | +10 m | — |
| km 18 | 1.1 km | 3.5 % | 4.1 % | +37 m | — |
Climb categories follow the road-cycling convention and rate the terrain itself (length and gradient) regardless of sport: Cat. 4 marks the easiest rated climbs, Cat. 1 the hardest, and HC (hors catégorie, “beyond categorization”) is reserved for the most brutal ascents. Short climbs below the Cat. 4 threshold stay unrated.
How to pace 20 km de Bruxelles.
Start under control
Just under half the route sits in the flat band and there is no steep ground anywhere – and yet this is not a course you run on even splits. You start in one of six waves from 10:00, the opening kilometres are crowded and downhill, and that is exactly where most runners lose the race, because the pace feels effortless. Then hold yourself back on the long rise to Avenue Louise: it costs more than 50 metres of climbing between kilometres four and seven without ever feeling like a hill.
Hold your rhythm
The real trap is the descent from kilometre thirteen. Four kilometres down into Woluwe hand you time, and if you take them with a long stride your quads are empty at the bottom. Run them under control, with a short, quick cadence.
Spend what is left
The race is decided on the Avenue de Tervueren from kilometre 18: a good kilometre at 3.5 percent with 18 kilometres already in your legs. Plan a deliberately slower split there rather than fighting to hold pace – the last 700 metres from Montgomery fall away again and give back what you spent on the climb. Late May in Brussels can already be warm by midday, and the later waves are out in the warmest hour: drink at the six water points early, not when you finally need to.
Training plan for 20 km de Bruxelles: 12-week build
Build the base
As an age-group runner you will be out here for something between 75 minutes and a good two and a half hours. The effort is aerobic throughout but far from uniform: the course is one long, barely perceptible climb, a rolling plateau, a long descent and then a genuine finishing hill. Changes of rhythm are the rule here, not the exception.
Train race pace
Two phases decide the race and both sit in the final third. The four kilometres down into Woluwe load the quadriceps eccentrically, immediately before the only real climb of the day. If you have only trained on the flat, the Avenue de Tervueren tells you so at once.
Rehearse the course
Build your preparation around exactly that sequence. Long runs with a deliberately quick downhill section followed by a one-kilometre climb at three to four percent reproduce the demand almost one to one. Add weekly threshold runs of 20 to 40 minutes for the flat passages, and a few uphill efforts started out of full race pace rather than from standing, so you do not come apart at the top. Downhill running belongs in the plan explicitly: it is the only way to accustom the muscles to eccentric braking.
Arrive fresh
Conditions are the second training factor. The last Sunday in May regularly brings 20 degrees or more to Brussels, the waves start at 10:00 and run into the late morning, and much of the route is open asphalt between buildings. Do two or three sessions in midday heat, rehearse your drinking at race pace, and prepare to run in a very dense field: 47,000 starters means you do not freely choose your pace over the opening kilometres.
Courses
Download the 20 km de Bruxelles course as a GPX file for your watch or bike computer.
Let YOUB adapt your plan for 20 km de Bruxelles dynamically
Ben connects your goal, the course, current load, recovery, and calendar. Your plan stays pointed at race day even when real life is not perfectly plannable.
Everything about 20 km de Bruxelles.
How long is 20 km de Bruxelles?
20 km de Bruxelles is 20.1 km long. That distance shapes how much aerobic endurance, pace durability, and race-specific work belong in the training plan.
How much elevation gain does 20 km de Bruxelles have?
20 km de Bruxelles has around 162 m of elevation gain over 20.1 km. That affects pacing, muscular load, and preparation for late-race sections.
What is the route profile of 20 km de Bruxelles?
20 km de Bruxelles is classified as Flat, averaging 7.9 vertical metres per kilometre. 48% of the route is flat, 32% climbs moderately (2 to 6%) and 0% is steeper than 6%.
What climbs does 20 km de Bruxelles have?
The hardest climb of 20 km de Bruxelles starts at kilometre 18, runs for 1.1 km at an average of 3.5% and gains 37 metres. 2 climbs are mapped in total.
Is 20 km de Bruxelles a loop course?
Yes, 20 km de Bruxelles is laid out as a loop: start and finish are in the same place.
Is there a GPX file for the 20 km de Bruxelles course?
Yes. The 20 km de Bruxelles course is on this page as a free GPX download — ready to import into Garmin, Wahoo, Komoot, Strava or any other app that reads GPX.
How should I prepare for 20 km de Bruxelles?
Preparation for 20 km de Bruxelles should account for 20.1 km, 162 m of elevation gain, current training load, and available training time. An adaptive plan helps place key sessions without ignoring recovery and real life.
What pacing strategy works for 20 km de Bruxelles?
The pacing strategy for 20 km de Bruxelles should reflect 20.1 km, 162 m of elevation gain, and your current fitness. Start controlled and keep margin for sections where the profile or fatigue makes target pace harder.
When does 20 km de Bruxelles take place?
20 km de Bruxelles takes place on May 30, 2027.
Where does 20 km de Bruxelles take place?
20 km de Bruxelles takes place in Brussels, Belgium.
How do I register for 20 km de Bruxelles?
Registration runs through the organiser: 20kmdebruxelles.be. YOUB shows you the course, elevation profile and training plan for your preparation.
