Semi-Marathon de Boulogne-Billancourt takes place on Sun, Nov 15, 2026 in Boulogne-Billancourt, France. The main route is 21.1 km.
- Date
- Sun, Nov 15, 2026
- Start
- Boulogne-Billancourt 🇫🇷
- Distance
- 21.1 km
- Climbing
- 124 m
- Level
- Open to all
The Semi-Marathon de Boulogne-Billancourt is a fast, officially measured 21.1 km road race through Boulogne-Billancourt, with an urban, Seine-side and Bois de Boulogne course featuring only 124 m of elevation gain.
What would it take you?
Pick the level closest to yours for an estimate of finish time on this course and the training a solid preparation needs.
Estimated finish
1:55–2:15
Peak-week training
5–7 h/week
A model estimate from distance, climbing and level, not a promise. Conditions, drafting and pacing move it.
IntervalCoach turns those weekly hours into a concrete plan built around your actual fitness. Start with this race as your goal
Your road to race day
Race day at Semi-Marathon de Boulogne-Billancourt is 10 weeks away. This is how a coach divides that time. The first phase starts now.
01Build4 weeks · Sep 7, 2026 – Oct 4, 2026
Progressive overload: training load climbs in waves, with harder weeks stacked on the base and planned recovery weeks that let the gains land.
02Peak3 weeks · Oct 5, 2026 – Oct 25, 2026
The hardest weeks of the plan: race-specific intensity at nearly full training load, sharpening exactly what this race asks for.
03Taper2 weeks · Oct 26, 2026 – Nov 8, 2026
Volume drops while intensity stays: short, sharp efforts keep the legs awake as fatigue drains away.
04Race week1 week · Nov 9, 2026 – Nov 15, 2026
Openers, rest and logistics. The work is done; the job now is arriving fresh.
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