Date
Sun, 14 Feb 2027
Start
10:00
Venue
Merthyr Tydfil Leisure Centre, Merthyr Tydfil to Coleg y Cymoedd, Parc Nantgarw, Nantgarw
Upper Boat, Rhondda Cynon Taf
Countdown
February
A full marathon run point to point from Merthyr down to Nantgarw, with no waymarking. You find your own way, so a GPS is your guide and 1,200 m of climbing is the price.
Key facts
01Route is unmarked, so you must navigate by GPS
0212-hour cut-off, with the course closing at 22:00
03Compulsory kit required; age 18 and over only
Create a free training plan for the Taff Xtreme Marathon
7-day free trial, no card required
The course
The route
Upper Boat
Distance42km
Total climb1,200m
StartElevation
0 kmDrag map to rotate41.0 km
Weather
Mid-February, Upper Boat
8°CTypical high
3°CTypical low
-4°CColdest in 20 years
46%Days with rain
Highs around 8°C and lows around 3°C, but it has dropped to -4°C. Rain on 46% of days. Pack for the cold end, not the average.
NASA POWER data, 2006-2025, the week either side of race day
2026 results
Who finishes, and how
#RiderTimeAvg speed
01Claire Walters05:02:458.4 km/h
02Amy Dyer05:04:038.3 km/h
03Bethan Long06:04:036.9 km/h
20
Women finishers
6:30:27
Median time
6.5 km/h
Median speed
Women · 2026 results, as published by the organiser.
How fast could you finish?
Get a prediction based on your recent training
Organiser
Training
Training for the Taff Xtreme Marathon
We don't do generic plans. We combine deep knowledge of this race's demands with your recent training, then build a plan with you that progresses as you do.
Beina integrates directly with your existing tools to understand your current fitness, and synchronise your planned sessions.
Intervals.icuWhat a Taff Xtreme Marathon plan targets
Typical sessions
42 km with 1,200 m of climbing
Time on feet and fatigue resistance
Fuelling and pacing for the whole event
What your weeks look like
Typical sessions
Long runs that build time on your feet
Tempo and threshold sessions to hold race pace
Back-to-back weekend runs for fatigue resistance
Not a generic schedule
Typical sessions
Built from your current fitness and the time you actually have
Adapts every week as Beina learns how you respond
Syncs your sessions straight to Garmin and Wahoo
One clear next session, never a wall of spreadsheet
Entries open now
Get your Taff Xtreme Marathon plan.
7-day free trial, no card required.
More events in February in United Kingdom
Shadowlands: Winter Trail SeriesSat, 6 Feb 2027 · Sunderland→Trails & Tarmac 12hr BYU - WinterSat, 6 Feb 2027 · Course and HQ just outside Crickhowell→Trails & Tarmac Winter 12 hour Back Yard UltraSat, 6 Feb 2027 · Powys→Wadsworth Trog “THE BEAST”Sat, 6 Feb 2027 · Old Town→Winterfold 55Sat, 6 Feb 2027 · Mickleham→Sidmouth Four TrigsSun, 7 Feb 2027 · Sidmouth→
