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Set at the spectacular, flat and smooth-surfaced Dorney Lake, near Windsor, the course takes onto the lake and around the perimeter of the water for the cycle and run. With fuel and water stations and chip-timed results we try and make it as easy as possible to get your pacing right, so that you can focus on your race and get the best possible time.

C-19 Plan
F3 Events has confirmed that this event will be going ahead as planned on Saturday 5th Sep 2020 in accordance with the COVID-19 safety measures. Learn more

Review summary

8 Reviews
  • Course
  • Organisation
  • Atmosphere


Steph E
"If it is very sunny, remember your suncream and sunglasses as there is no shade..."


Charlie M
"Really enjoyed my first duathlon. Perfect weather and greatly equipped venue...."


Gemma D
"This was poorly organised no direction of what was going on. Say it was time..."
See all reviews

How to enter the Dorney Lake Autumn Triathlon

  1. Half Marathon

    Run 13.1mi
    Event passed
  2. 10k

    Run 10km
    Event passed
  3. 5k

    Run 5km
    Event passed
  4. 15k

    Run 15km
    Event passed
  5. Super Sprint

    Duathlon: Run 2.5km, Bike 12km, Run 2.5km
    Event passed
  6. Sprint

    Duathlon: Run 5km, Bike 20km, Run 5km
    Event passed
  7. Olympic

    Duathlon: Run 10km, Bike 40km, Run 5km
    Event passed

Dorney Lake Autumn Triathlon routes


First Run Course

  • The run will start next to the Main Registration Marquee and will be an out and back course measuring 2.5km.
  • The Super Sprint Duathlon run will be 1 out and back lap, the Sprint Duathlon run will be 2 out and back laps and the Olympic Duathlon run will be 4 out and back laps.
  • Once completed, competitors will proceed into the RUN IN entrance of the transition area.

Bike Course

  • The course consists of approx. 5km laps up and down the side of the famous lake.
  • Super Sprint Duathlon will complete 2 laps, the Sprint Duathlon will complete 4 laps and the Standard Duathlon will complete 8 laps.
  • Please note that it is the competitors responsibility to count the number of laps they have ridden.

Final Run Course

  • The final run course is once again an out and back loop equal to 2.5km.
  • The Super Sprint distance will be 1 lap and the Sprint & the Olympic distances will be 2 laps.


  • The 5km, 10km, 15km & half marathon courses are laps around the famous rowing lake.
  • The course is fast and flat and takes place on tarmac paths and closed roads.
  • This is a perfect course for first time runners or those looking to get a PB

Event Details

What’s Included
  • Chip Timing
  • Bespoke Medals
  • Onsite Parking
  • Baggage Area
  • Toilets
  • Ambulance Services
  • Marked Course
  • Feed Stations
  • Marshalled Course
  • Onsite Retailers
Raceday Logistics


You will collect your race numbers on the day of the event when you come to register. You will also collect your timing chip at registration on the day.


08:00am- Duathlon Start

09:00am Venue & Registration opens for 5km, 10km, 15km & Half Marathon

10:45am - Half Marathon, 15km, 10km & 5km Start

Please arrive at least 45 minutes before the start of your race in order to complete the registration process.

Kit List
  • Duathlon competitors are expected to supply their own bike in good working order.
  • Helmets are also compulsory

Spectator's are very welcome! Create that amazing atmosphere as you cheer on your family or friends from start to finish.


To volunteer please email [email protected] and one of the F3 events team will contact you.

Frequently Asked Questions

At what time does the Windsor Autumn Half Marathon start?
The Windsor Autumn Half Marathon starts at 10:45am. Competitors should arrive from 9:00am.
Is the Windsor Autumn Half Marathon family-friendly?
Yes. The traffic free setting and easy car-parking makes it easy for spectating family members to move around and create a friendly atmosphere, or family members can sign up for the shorter-distance races. For safety purposes, dogs and prams should not be brought onto the course at any time.
Can you sign up for the Windsor Autumn Half Marathon on the day?
Yes. You can sign up on the day, but any entries received on the day or in the two-week build-up will incur a £5 fine.

Dorney Lake Autumn Triathlon weather forecast

Partly cloudy throughout the day.

Predicted highs
Predicted lows
IconLight breeze possible, up to 8mph

Meet the organiser

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F3 Events

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F3 Events
Offering fun, friendly, family, fast and focused events across the South. F3 Events was set up in 2006 and has been one of the leading sporting event organisers along the Thames Valley for the past 10 years. Our mission is to organise, deliver and provide first class sporting events along the Thames Valley to aspiring athletes from complete beginners to elites athletes.



Dorney Lake Autumn Triathlon reviews (8)

3.7 out of 5 stars

  • Course
  • Organisation
  • Atmosphere
  • G

    Gemma D

    Did the Half Marathon in 2019

    This was poorly organised no direction of what was going on. Say it was time chipped find that hard to believe as there was no chip monitor at start line or around the course for spilts. Atmosphere on the course was pretty poor. Wouldn’t do it again.
  • D


    Did the event in 2019

    Was ok... the running course was quite boring , could be better ... wasn’t many people to. Cheer you up
  • D

    Damien M

    Did the event in 2019

    Whilst the course was flat, it was monotonous due to the short repetitive laps. There were very few participants and very few spectators, resulting in a lack of atmosphere.
    The event was poorly organised, with very little actually set up in time for competitors arrival. For example, when we arrive (after the stated arrival time), we were sent around in a circle and back to the entrance instead of being directed to the car park (because the marshalls had forgotten to remove/change signage). When I pointed this out to the marshall directing parking traffic, I received an aggressive response.
    Finally, the goody bag was seriously lacking.
    Note I have participated in literally hundreds of events and this has to be the worst I've done, largely due to the organisation.
  • Did the event in 2018

    An extremely well organised event with a beautiful course. The weather couldn't have been better. First class and look forward to next year.
  • Did the event in 2018

    This was the best Saturday of October! I attended this race with friends and it was my second 10k that I have taken part in. The setting was just perfect. The atmosphere was joyful and the race organisers and marshals were friendly and helpful. This location is a new favoured race spot for me and so I will be back for more very soon!
  • Did the event in 2018

    Really enjoyed my first duathlon. Perfect weather and greatly equipped venue.
  • Did the event in 2018

    If it is very sunny, remember your suncream and sunglasses as there is no shade at all on this course.
  • Did the event in 2018

    Very good event. Well organised. My first run for 11 years and I couldn't have picked a better one. See you next year
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