How to Choose Your First Ultra Marathon

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To choose your first ultra marathon, start with a race you genuinely want to do, then pick a supported 50km or two-day multi-stage on terrain like the trails you already train on, and give yourself 12 to 24 weeks to prepare. Here’s how to make each of those decisions.

Most of the advice on choosing a first ultra marathon tells you to start small, build up, and earn the big race. I do not think that is right, and our own numbers back that up. More than half the people who finish their first ultra with us had never run a marathon when they registered.

What they had was a race they wanted to do. That matters more than the distance.

Pick the race that excites you

The first ultra that goes well is the one you train for, and people train for races they care about. Nobody does 16 weeks of long runs for a 50km they entered because it seemed sensible. They do it for the race they have had on a list for three years, whether that is a desert, a mountain range, or a two-day event with a camp in the middle.

So start with the race, not the distance. If a week in Wadi Rum is the thing that gets you out of the door in January, that is the right first ultra, and the rest of this article is about making it work.

How far should your first ultra marathon be?

The distance question is still worth asking, but as a second question. A 50km is the easiest to train for alongside a job. A supported two-day 110km multi-stage is, for a lot of people, a better first ultra than 100km in one go, because you get to eat, sleep and start again rather than running through the night. A week-long stage race is a big first race, and people do it every year, but it needs more time and more planning than a weekend one. What I would leave for later is a 100 miler, a self-sufficient race where you carry all your food, or anything with serious altitude.

How the main first ultra formats compare:

Format	Training time	Typical finish time	Good first ultra?
50km	12–16 weeks	5–9 hours	Yes, for most people
Two-day 110km multi-stage (supported)	12–16 weeks	12–20 hours	Yes, for marathon runners
100km single stage	20–24 weeks	14–30 hours	Possible, but harder
Week-long stage race	20–24 weeks	30–80 hours	A big first race that needs more planning
100 miles, self-sufficient or high altitude	20–24 weeks	18–40 hours	Leave for later

Should your first ultra be single stage or multi-stage?

A single stage race is one continuous effort. A multi-stage race is split into days, with a camp in between. Same distance, different problems.

In a 100km single stage, the things that end your race are night running, pacing too hard early and losing the ability to eat. In a two-day 110km multi-stage, the things that end your race are feet, not eating enough in camp, and starting day two cold and stiff.

If you have done long events before and like the idea of pushing through, go single stage. If you like the idea of a camp, a shared tent and a second start line, go multi-stage. Neither is the soft option.

How long do you need to train for your first ultra?

A 50km needs around 12 to 16 weeks of consistent running off a marathon base, or equivalent long-run fitness. A 100km or a week-long stage race needs 20 to 24.

Weeks matter less than whether you actually do the training each week. Three runs a week, every week, for four months gets people to the finish. Six runs a week for a fortnight and then a month off does not. If you cannot see yourself doing the training between now and race day, enter the following year’s edition instead. The race will still be there.

You can find and download one of our free ultra marathon training plans here.

Pick terrain you already run on

Terrain changes the race more than distance does. A flat 50km on towpath and a 50km in the Lake District with 2,500m of climbing are not versions of the same thing.

Look at where your long runs actually happen. If they are on road and park trails, a first ultra with technical mountain descents will hurt in ways fitness does not fix. If you walk a lot of hills, a hilly race may suit you better than a flat one, because hiking the climbs is the plan for everyone, not just the back of the field.

For a first ultra marathon, runnable trail with some climbing is where most people do well.

Supported or self-sufficient: which is better for a first ultra?

Supported means checkpoints with food and water, your bag moved between camps, and medical on the course. Self-sufficient means you carry a week of food on your back and the organiser gives you water and a tent. Marathon des Sables is the famous self-sufficient race.

Do a supported race first. Carrying 8kg of food adds a layer of planning that has nothing to do with running, and you want to find out whether you like ultras before you find out whether you like freeze-dried meals.

Home or abroad

A UK race is cheaper, you can recce the route, and the climate is one you already train in. An overseas race is usually the thing that got you interested in the first place, and there is nothing wrong with that being the reason you enter.

If you go abroad first, pick somewhere the weather is not the main problem. Madeira or Slovenia in the right season is fine. Jordan in the desert or Kenya at altitude is a different preparation, and you will enjoy them more once you have a finish behind you.

Check what the organiser actually provides

This is the bit people skip, and it is the bit that matters when it goes wrong. Before entering, find out:

• how far apart the checkpoints are
• what the cut-offs are and whether a steady walker can make them
• what medical cover is on the course, not just at the finish
• whether there is live tracking
• how long the event has been going and what last year’s finishers say
• what happens if you drop at a checkpoint

If you cannot find the answers on the website, email and ask. An organiser who takes a week to reply before the race is not going to be quicker during it.

Mistakes I see every year

• Entering the long distance because the short one “did not sound like enough”
• Not looking at the elevation profile
• Treating the cut-off as a pace plan
• Never having eaten on a run before race day
• New shoes, new pack or new socks on the start line
• Going out at marathon pace and walking the last 20km

None of these are fitness problems.

How to choose your first ultra: the short version

The first ultra that goes well is the one you train for properly, on terrain you like, at a distance that leaves you wanting the next one. Get that right and there are ten years of races ahead of you. Pick the wrong one and a lot of people never come back.

The best ultra marathons for beginners at Ultra X

Every Ultra X UK event has a 50km alongside the 110km single stage and the two-day 110km multi-stage. Ultra X England, Ultra X Wales and Ultra X Scotland all work as a first ultra, and you can come back for the next distance on a course you already know. For an overseas first, Ultra X Madeira and Ultra X I Feel Slovenia have shorter distances in the same week as the main races.

Frequently asked questions

Can I run an ultra marathon without running a marathon first?

Yes. More than half of first-time ultra finishers at Ultra X had not run a marathon when they registered. Build the long run to around 30km in training so the distance is not a complete unknown.

How do I get into ultra marathons?

Start with a race you genuinely want to do, then give yourself 12 to 16 weeks of consistent training for a supported 50km on terrain you already run on. Build the long run gradually, practise eating on the move and check the cut-offs suit a steady walking pace.

What is a good first ultra marathon for beginners?

A supported 50km on runnable trail with some climbing suits most beginners. If you are already a marathon runner, a supported two-day multi-stage is also a good first ultra.

Is 50km a good first ultra?

For most people, yes. It needs ultra-specific preparation and can still be finished in daylight on most courses.

Should my first ultra be a multi-stage race?

A supported two-day race with stages of around 55km is a good first ultra for a marathon runner. A week-long self-sufficient race is not.

How long should I train for my first ultra?

Around 12 to 16 weeks for a 50km if you already have a marathon base or equivalent long-run fitness, and 20 to 24 weeks for a 100km or a week-long stage race.

How long does a first ultra take?

A 50km usually takes five to nine hours depending on terrain. A 100km takes twelve to thirty. Check the cut-offs for your race against your realistic walking pace, not your running pace.

What is the easiest ultra marathon in the UK?

No ultra is easy, but a flat or rolling 50km with checkpoints every 10km or so is the most accessible ultra marathon for beginners. Our guide to UK ultra marathons lists options from beginner to advanced.