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Challenge description

Challenge description

Lon Las Cymru is a 250 mile non-stop race from Holyhead to Cardiff Bay down the centre of Wales, crossing several mountain ranges. You will follow Sustrans cycle route 8 all the way, with the last 55 miles along the 'Taff Trail'.

Mostly on road, you will be virtually self sufficient which will make this an incredibly difficult challenge. Running for 250 miles alone is a tough enough feat, but that mileage mainly on roads will be painful. In addition, there are some big climbs along some of the route of 500metre+ elevation.

A time limit will be set at 88 hours, meaning that you can complete the challenge if you keep moving at around 2.9 mph. A halfway time limit will also be strictly enforced. This will be no-nonsense, basic and low key challenge designed to push you to your limits.


12th - 15th October 2023




Enter Lon Las Cymru


Runners must have extreme ultra-running experience with a 100 mile finish being the minimum pre-requisite. Please only apply and make payment if you meet the required pre-requiste (entries can be rejected and refunded at the RD's discretion).


No refunds, transfers, or deferrals.

Contact us

Questions? Contact us

Email Mark if you'd like to know more about Lon Las Cymru:, or follow our Facebook group!

Registration information

Registration information

Starting at Holyhead port/station, 7am you will travel south following route 8.

What's included

What's included

  • A professional track timing system (provided by Track/Trail). 

  • We will supply you with WATER ONLY at vehicle checkpoints, which will be approximately every 25 miles.

  • Comprehensive maps.

  • Finishers t-shirt.

  • Bespoke medal.



  • No refunds, no deferrals.

  • You must not come if you feel unwell/have any Covid symptoms.

  • There will be little to no shelter at checkpoints, so you must be prepared for bad weather and willing to 'rough it'.

  • You are allowed ONE average sized drop bag. (We cannot transport any other luggage)

  • You will be allowed access to your bag (1x bag per runner) every 50 miles.

  • Shops and pubs are allowed.

  • You will be constantly monitored by tracker to ensure that you are following the correct route - GPX navigation is allowed.

  • No outside assistance is allowed.

  • No crews allowed.

  • No pacers allowed.

  • No sticks allowed.

  • You cannot use hotels/BnB's/hostels/friends houses.

  • Friends and family can offer verbal support along the route.

  • Use of headphones is strictly prohibited.

  • If you drop out, you must arrange your own way home, however we will try to take you to the nearest train station when it is convenient, so please have a drop out plan.

  • No awards will be made to any runner finishing outside the allocated time limit.

During the race

During the race

During the race, you must:

  • carry a mobile phone and have a backup phone in your drop bag and extra power (vehicle charging will be limited).

  • wear hi-viz clothing for the duration of the event.

  • wear a head torch and flashing LED lighting in all directions during night running.

  • carry a fully (seamed) waterproof jacket at all times.

  • carry a space blanket and a bin liner at all times.

  • have a sleeping bag in your drop bag.

  • carry money and a credit card.

  • have a means of carrying upto 2 litres of water and high energy foods to last between drop bag CP's (every 50 miles).

  • reach the halfway point (Llandidloes) in no more than half the full allocated time limit.

  • run facing traffic where possible. The route will be very low on traffic but some sections can be busy.

During the race, you can:

  • use local shops and pubs on route.

  • use GPX files of the Lon Las Cymru Sustrans route 8.

Race results

Race results

View race results for Lon Las Cymru, 2017

View race results for Lon Las Cymru 2021



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