Your plan in four answers
Set for September 5, 2027, about 45 weeks out.
- Distances
- Half marathon
- Terrain
- Flat
- Field
- A record 17,876 finishers in 2026
- Taper starts
- August 24, 2027
Course
The Big Half course
A point-to-point half marathon through four east and south-east London boroughs, starting beside Tower Bridge and finishing near the Cutty Sark in Greenwich. The opening kilometres head east through the Limehouse Tunnel into Canary Wharf, with short rises on the tunnel exit and on the way into the Wharf.
Read the full course notes
The route then twists back west through Limehouse and a brief cobbled stretch in Wapping before crossing Tower Bridge just past halfway, the highlight of the morning. The second half runs south of the river through Rotherhithe and on towards Greenwich, quieter in places, and the only real sting is a short bridge climb about 500 m from the finish before a downhill push into Greenwich town centre. Canary Wharf's towers scramble GPS, so trust the course markers over your watch there.
- Terrain
- Flat
- Distances
- Half marathon
- Field
- A record 17,876 finishers in 2026
- Weather on race day
- Early September in London is usually mild, roughly 13–21 °C across the day, so expect the mid-teens at the 9:00 start and warmer by the finish. Humidity can make a sunny morning feel warmer than the number suggests, so start conservatively and take water early.
What to train for
This course rewards steady pacing more than hill strength: the climbs are a tunnel exit, a ramp into Canary Wharf and one bridge near the end.
Build toward long runs of 16–19 km with the final 5 km at half marathon effort, and add a weekly tempo of 20–30 minutes at threshold.
Run a few sessions by feel without looking at your watch, since GPS drifts around Canary Wharf, and save something for the bridge 500 m out so you can attack the downhill into Greenwich.
Sample week
A sample Big Half training week
A week from the middle of the build, about six weeks out. Your plan sets the real distances and paces from your own fitness and adjusts them every week as you train.
- Monday
- Rest, or 20 minutes of mobility
- Tuesday Key session
- Intervals: 5 × 1 km at 5K to 10K effort, easy jog between
- Wednesday
- Easy run, 8–10 km
- Thursday Key session
- Goal-pace run, 11 km with 6 km at race pace
- Friday
- Recovery run, 6 km, or cross-train
- Saturday Key session
- Long run, 16–19 km easy
- Sunday
- Easy run, 6 km, then 6 relaxed strides
Your build to race day
Taper
Tapering for the Big Half
Start the taper ten to fourteen days before race day. Cut your weekly volume by about a third, then by half in race week, and keep a few short efforts at race pace so your legs stay sharp. The course is flat, so pacing decides the day: rehearse your goal pace in short segments during race week. With the race on September 5, 2027, your taper starts around August 24, 2027.
Also in Claude
Ask Claude for this plan
Add AthleteSpace to Claude once, then paste this prompt and put in your own numbers.
Build me a training plan for the The Big Half (Half marathon) on September 5, 2027. I run [distance] a week, [days] days a week, easy pace [pace].
Big Half training questions
How long should I train for the Big Half?
Most runners give a half marathon twelve to sixteen weeks of focused training on top of an existing base. The plan above counts back from your actual race date, so if you have less time than that it builds the best plan the remaining weeks allow rather than pretending you have longer.
Is the Big Half course hilly?
Flat. A point-to-point half marathon through four east and south-east London boroughs, starting beside Tower Bridge and finishing near the Cutty Sark in Greenwich.
What is the weather usually like at the Big Half?
Early September in London is usually mild, roughly 13–21 °C across the day, so expect the mid-teens at the 9:00 start and warmer by the finish. Humidity can make a sunny morning feel warmer than the number suggests, so start conservatively and take water early.
When should I start tapering for the Big Half?
Start the taper ten to fourteen days before race day. Cut your weekly volume by about a third, then by half in race week, and keep a few short efforts at race pace so your legs stay sharp. The course is flat, so pacing decides the day: rehearse your goal pace in short segments during race week. With the race on September 5, 2027, your taper starts around August 24, 2027.
Do I need an account to get a Big Half training plan?
No. The plan above builds in your browser with no account, no email, and no card. Make a free account only if you want to keep it, log your runs against it, and have the coach keep adapting it as your training goes.