Hosted by Action Challenge, the Windsor 50 Ultra Challenge is a 50km Ultra, a historic 25 km, or a 10km challenge. From our Windsor Racecourse basecamp 2000 adventurers will head out on looped routes through the Great Park with fantastic views of the Castle, on to Runnymede, along the Thames Path, and takes in some wonderful surrounding countryside. 

You’ll get full support all the way, and a celebration finish back at basecamp. It’s a great way to kick off the Ultra Challenge® season, and start to get in shape for summer.

Use code 25%CHARITY until 31 October 2025 for 25% off your registration fee.

Charity sponsorship

Pay a lower registration fee and fundraise for Terrence Higgins Trust.

Mixed funding

Pay a higher registration fee your place and fundraise towards a lower target.

Please check the Windsor 50 Ultra Challenge website for the most up-to-date prices and special offer deals.

As part of our team, you’ll receive:

• A Terrence Higgins Trust t-shirt to wear with pride
• Expert fundraising advice and unlimited support from our dedicated team
• Pre-event training guidance to help you prepare

On the day, you’ll enjoy:

• Rest stops with drinks and refreshments
• All meals and snacks included (depending on your chosen distance)
• Access to medics, massage services, and pace walkers
• A finisher’s medal, t-shirt, and a glass of bubbly to celebrate your achievement

Your support and fundraising help fund vital services including our one-of-a-kind sexual health helpline, HIV testing, counselling, and peer support programmes.

We are working to ensure that there will be no new HIV cases in the UK by 2030. Everyone living with HIV will be diagnosed, in treatment and care, free from stigma and able to take advantage of life’s opportunities.

Lace up those walking boots and trek to help us end new cases of HIV in the UK by 2030. To register or to find out more, visit the Windsor 50 Ultra Challenge site.

Please don’t forget to choose Terrence Higgins Trust as your charity when signing up!

Action Challenge Ultra events are for a wide range of fitness & ages – and UK’s #1 series of treks & trial runs. Choose your challenge – do it at your pace, and there’re 18 events in the UK series. Action Challenges support enables you to go further, whilst enjoying the great outdoors & camaraderie. 

There’re marquee rest stops, lots of food & drink, medical & massage teams, with a fully signed route & GPS tracking to guide you. 

A big finish-line celebration awaits with an amazing sense of achievement, and once the aches subside you’ll feel energised, and up for more of life’s real challenges! 

See all the 2026 Ultra Challenge events

Any questions or want to tell us you're signing up to a trek? Contact our Fundraising team or checkout Windsor 50 Ultra Challenge factsheet.