Semi-marathon des Lions.
The Semi-marathon des Lions is a flat two-lap half marathon on the Seine bank at Rueil-Malmaison, staged by the local Lions Club as a charity race. It offers a personal-best course with no meaningful climbing, and the real test is the second lap, run after the field has already passed the finish area once.
Semi-marathon des Lions 2027: Course, Route Profile & Map
The start is at the entrance of the Parc des Bords-de-Seine and the finish is on the park's stadium. In between, the half runs the main circuit along the Seine twice, the same loop the 10 km covers once; only in a few places does the longer race branch off for a few hundred metres to make up the full distance. After the first lap the course passes right in front of the stadium, where an intermediate control is set up.
The profile is as level as a riverside course gets: the whole route sits within a band of a little over ten metres, and there is no climb that breaks your rhythm. The ascent figure on paper comes from many small ripples and ramps at the bank access points, not from a hill.
The race is a proper road event and a charity fundraiser at once: all of the profit goes to social projects supported by the Lions Club of Rueil-Malmaison. The 16th edition in 2027 moves from the previous year's April date to early March. With about 1,850 half-marathon finishers in 2026 you will rarely run alone, and bibs can be collected the day before.
| Start | Length | Ø | Max. | Gain | Cat. |
|---|
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 Semi-marathon des Lions.
Start under control
On a course without climbs, even pacing is the whole strategy. Fix a goal pace and hold it from the first kilometre; you do not need to correct for the small ripples along the bank, run them on effort rather than on the watch.
Hold your rhythm
The race is decided on the second lap. When you pass the stadium for the second time the finish feels close, yet more than ten kilometres remain. If you switch off mentally there or underestimate a stretch you already know, kilometres 12 to 18 are where the time leaks away.
Spend what is left
The trap is the start: the 10 km field has been out an hour earlier, the half-marathon runners set off fresh on a dead-flat course, and the first kilometres feel too easy. Ten seconds per kilometre too fast there is paid for on the second lap.
Training plan for Semi-marathon des Lions: 12-week build
Build the base
For most age-group runners this half takes between 1:35 and 2:30; the 2026 average was just under two hours. That is a continuous aerobic effort just below threshold, with no climbs to force changes of pace. The demand is pure endurance at a constant speed.
Train race pace
The race is decided on the second lap, where you have to hold the same pace over the same ground on tired legs. Train for exactly that: tempo runs of 8 to 12 kilometres at half-marathon pace, and long runs with the final third at race pace, prepare you for that phase.
Rehearse the course
Because the course is flat, you need no hill training. More valuable is a reliable sense of pace: runs on flat loops where you hit a set pace without checking the watch pay off directly here.
Arrive fresh
The early-March date puts the whole build in winter. Schedule the key sessions on asphalt despite the cold and dark, so legs and tendons adapt to fast running on a hard surface, and expect cool conditions by the river on race day.
Courses
Download the Semi-marathon des Lions course as a GPX file for your watch or bike computer.
Let YOUB adapt your plan for Semi-marathon des Lions 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 Semi-marathon des Lions.
How long is Semi-marathon des Lions?
Semi-marathon des Lions is 21.1 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 Semi-marathon des Lions have?
Semi-marathon des Lions has around 114 m of elevation gain over 21.1 km. That affects pacing, muscular load, and preparation for late-race sections.
What is the route profile of Semi-marathon des Lions?
Semi-marathon des Lions is classified as Flat, averaging 5.4 vertical metres per kilometre. 63% of the route is flat, 17% climbs moderately (2 to 6%) and 0% is steeper than 6%.
Is Semi-marathon des Lions a loop course?
Yes, Semi-marathon des Lions is laid out as a loop: start and finish are in the same place.
Is there a GPX file for the Semi-marathon des Lions course?
Yes. The Semi-marathon des Lions 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 Semi-marathon des Lions?
Preparation for Semi-marathon des Lions should account for 21.1 km, 114 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 Semi-marathon des Lions?
The pacing strategy for Semi-marathon des Lions should reflect 21.1 km, 114 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 Semi-marathon des Lions take place?
Semi-marathon des Lions takes place on March 7, 2027.
Where does Semi-marathon des Lions take place?
Semi-marathon des Lions takes place in Rueil-Malmaison, France.
Which distances does Semi-marathon des Lions offer?
Semi-marathon des Lions offers 2 distances — Semi-marathon: 21.1 km; 10 km: 10 km.
How do I register for Semi-marathon des Lions?
Registration runs through the organiser: semimarathondeslions.com. YOUB shows you the course, elevation profile and training plan for your preparation.
