How far is an ultra marathon?

An ultra marathon (or ultra run) is an event that covers any distance longer than a standard marathon – any run longer than 26.2 miles, or 42.195 kilometres (km). Popular distances for ultra marathons include 50km and 100km, or 50miles and 100 miles. Some of the events will be non-stop runs and others will be spread over a number of days with breaks. Ultra challenges are great events that come in a variety of forms including road races, treks and trail runs.

How long do I need to train for an ultra marathon?

Unlike fun run distances such as 5k or 10k, you aren’t just going to be able to turn up on the day and expect to be able to compete. Ultra runs require high fitness levels just to reach the finish line so you’re going to have to put in some serious training. Understandably, people don’t tend to go from a nothing straight to the ultra distances, but if you do then you run a high risk of injury. As part of your training and to build up to these distances you will probably want to first attempt events at shorter distances such as 10k races, half marathons and the standard marathon distance first. Check out our training plans to help you prepare for race day.

How do I get a Macmillan charity place for an ultra marathon?

Getting a charity place at running events is a fantastic way to fundraise for people living with cancer. To run for charity, you can register for your chosen ultra marathon on our website. It is a great way to guarantee your place as well as raising money for a good cause. Registration fees and fundraising pledges will vary between different events. If you have your own place in the race already and would like to run for us, you can still sign up for the ultra marathon event. There's no minimum sponsorship, just fundraise as much as you can! Either way, you will receive a fundraising pack with great tips to help you hit your fundraising target and training advice best suited your challenge as well as a Macmillan running t-shirt or vest to wear on race day.

Am I allowed to walk during an ultra marathon?

Considering the distances involved walking is usually fine at most events, whether it’s a mixture of walking, jogging and running or just walking. However, some events may have time limits, especially if the event is on closed roads. If you think you are likely to walk then it’s always worth checking with the event organiser that they welcome walkers and what the cut off time for finishers will be.

Can I wear headphones during an ultra marathon?

While some races may allow you to wear earphones or bone conduction headphones many discourage or even ban participants from wearing them. This is mainly a safety issue. If you can't hear other runners around you or traffic then the risk of collisions and injury is much greater. Also, the atmosphere at running events and it is a shame to miss out on it.

How many calories do you burn during an ultra marathon?

On average you burn around 100 calories per mile while running but the exact figure will depend on a number of factors that include how fast you run, your body mass and the terrain that you are running on. More hills means more effort, which in turn leads to more calories being burnt.

What should I eat before my ultra marathon?

Carbohydrates are vital to fuelling your training and race effectively. High quality, slow-release complex carbohydrates include oatcakes, sweet potatoes and whole grains. Protein provides the essential nutrients you need to heal damaged muscle fibre and tissues. You can get these proteins from lean meats, fish, nuts, sprouting seeds and tofu. We have lots of information on preparing your body for your event.

What should I eat during an ultra marathon?

Because of the distances involved in ultra challenges you are going to need to take on food as well as drinks during the event. Most organised events will have feed stations where you can take on vital energy but between those stations you are going to need to take on fuel regularly. Unlike in shorter races where your effort is very high and taking on and digesting food is very hard for the body to do so effectively, ultra events for most are a little different. Your exertion levels won’t be consistently so high so eating and digesting becomes a bit easier. As well as sports drinks and gels to get sugars back into your body you will need to top up your store of carbohydrates. Easy options include: salted peanuts, salted pretzels rice cakes and baby food pouches. What you will want to eat will largely depend on the pace that you are running and the length of the challenge.

How should I pace my ultra marathon?

A race pace is the average time it takes you to complete each kilometre, mile or section of the race. There are various training plans and ways to run ultra marathons and it might take some time to find out what works best for you. Some people prefer to run a steady and consistent pace where each split is tackled at the same speed. Others prefer to run slower at the start of the race and speed up as they continue through (negative splits). The reverse of this is called positive splits, which is when you go out fast and trying to hold on but accepting that the second half of your race will probably be a bit slower (positive splits).

What should I wear while running an ultra marathon?

With a lot of events, when you choose to run and fundraise for Macmillan you will receive a running t-shirt or vest but what else should you wear? The most important thing is to be comfortable and take into account the conditions you will be running in. If it's likely to be hot think about UV protection, running caps, performance sunglasses, and sunscreen. If it's going to be cooler then consider running tights and multiple layers rather than anything heavy. Depending on the distance you are running you will want to consider a running backpack or running belt so you can carry gels, fluids and food with you. The key is making sure you have trained in what you are wearing, and that you are comfortable in it. Check out our full range of Macmillan running kit.

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Ultra Challenge Series

Whether you’re a seasoned trekker, trail pro-runner or just getting started, there’s an Ultra Challenge for you.

About Ultra Challenge

Whether you’re a seasoned trekker, trail pro-runner or just getting started, there’s an Ultra Challenge for you. From stunning coastal scenery, to rolling green hills and riverside pathways, you’ll be fully supported on route from start to finish for an unforgettable day. Ready to be an Ultra Challenger?

As Charity Series partner, you’ll receive 50% off Charity Registration Places with Macmillan.

Ultra Challenge series events

South Coast Ultra Challenge

06 - 07 September 2025
East Sussex BN26 5PH
Thames Path Ultra Challenge

13-14 September 2025
London SW15 2NF
Thames Bridges Trek

13 September 2025
London SW15 2NF
Thames Moonlight 10 Walk

12 September 2025
London SW15 2NF
Chiltern 50 Ultra Challenge

27 September 2025
Oxfordshire RG9 3AP
Kent Downs 50 Ultra Challenge

11 October 2025
Kent ME14 1QN
London Halloween Walk

25 October 2025
London SE11 5SS
London Winter Walk

24 January 2026
London SE11 5SS
Bath 50 Ultra Challenge

28 March 2026
Bath and North East Somerset BA1 9BU
Windsor 50 Ultra Challenge

18 April 2026
Windsor and Maidenhead SL4 5JJ
Isle of Wight Ultra Challenge

02 May - 03 May 2026
Isle of Wight PO30 2JB
Jurassic Coast Ultra Challenge

16 - 17 May 2026
Poole BH15 1JJ
London 2 Brighton Ultra Challenge

23 - 24 May 2026
London TW9 2SF
Lake District Ultra Challenge

06 - 07 June 2026
Cumbria PO30 2JB
Cotswold Way Ultra Challenge

13 - 14 June 2026
Bath and North East Somerset BA1 2NQ
North Yorks Ultra Marathon

20 June 2026
United Kingdom YO12 5NL
Peak District Ultra Challenge

04 - 05 July 2026
Derbyshire DE45 1AQ
Gower Peninsula Ultra Challenge

18 - 19 July 2026
Wales SA3 1LN
South West Coast 50 Ultra Challenge

25 July 2026
Somerset TA24 6SL
North Downs 50 Ultra Challenge

01 August 2026
Surrey GU2 7AD
London Summer Walk

22 August 2026
London SE11 5SS
South Coast Ultra Challenge

05 - 06 September 2026
East Sussex BN26 5PH
Thames Path Ultra Challenge

12-13 September 2026
London SW15 2NF
Thames Bridges Trek

12 September 2026
London SW15 2NF
Kent Downs 50 Ultra Challenge

10 October 2026
Kent ME14 1QN
London Halloween Walk

24 October 2026
London SE11 5SS

View more hiking and walking events

Ultra Challenge FAQs

General event questions

What is an Ultra Challenge?

The Ultra Challenge is a series of 21 events set across stunning locations across the UK. Choose your distance from 10km to 100km, and then walk, jog or run at your own pace will full support from start to finish.
Can I run an Ultra Challenge?

Choose to run, walk, jog or mix it up! (Please note, Winter Walk, Halloween Walk and Thames Bridges are walking only events)

How to register FAQs

How can I register for an Ultra Challenge?

Click through to our Macmillan Landing Page, choose your event location and fundraising type, and follow the steps to complete your registration.
There are 3 registration options to choose from including:

Charity Registration – You pay the lowest registration fee and agree to a fundraising pledge for Macmillan.
Mixed Fundraising – You pay a higher registration fee than Charity Registration but have a lower fundraising pledge.
Self-Fundraising – You pay the full registration fee and fundraise what you can.

Each distance will have different entry fees and fundraising pledges.
Already have your own place on an Ultra Challenge and would like to fundraise for Macmillan? Please contact hiking@macmillan.org.uk.
How do I cancel my place?

Please contact the Action Challenge event organisers directly if you wish you cancel your place, by filling in this cancellation form.
How do I defer my entry?

Deferrals are managed by Action Challenge. You can request to defer your place by completing this defer request form.
Can I amend my registration?

Changes can be made up until 2 days before a challenge. If you need to make any amendments to your registration, please let the event organisers know by completing this registration changes form.

Fundraising support FAQs

How much do I have to fundraise?

Your fundraising pledge will depend on your registration type, and the distance you have chosen. More information on fundraising options can be found on each event page.

If you are using your own place to fundraise, there is no minimum pledge.
How can I set up a fundraising page?

Once registered, you will receive an email from Action Challenge with a link to set up your Macmillan JustGiving Page. If you haven't received your link, please email to let us know at hiking@macmillan.org.uk.
Can I fundraise as a team?

You absolutely can! JustGiving has full guidance on creating your team page.

Training FAQs

How can I train for my Ultra Challenge?

Whether you just to walk, jog or run your distance (or a bit of both) we’ve got the right training plan to help you feel your strongest, most prepared self on event day.

Hiking Training Plan
Running Training Plan