The Marreg.
The Marreg is a point-to-point ultra that starts at Foel Drygarn near Crymych and finishes on the Pembrokeshire Coast Path, entirely inside the Pembrokeshire Coast National Park. The 50-mile label hides roughly 86 kilometres, and most of them run along the coast, where short, very steep ramps keep breaking your rhythm.
The Marreg 2027: Course, Elevation & Route Profile
The course falls into two distinct halves. The first quarter crosses the inland hills: from the start at Foel Drygarn you climb straight away towards 400 metres, then follow open hill trails and woodland. Around km 15 you drop below 100 metres, only to face the hardest ramp of this section from km 17.3, close to a kilometre at nearly 17 percent on average. The route then holds its height for several more kilometres before it drops towards sea level for good around km 26.
From there the race stays close to sea level for almost 60 kilometres, and it is still anything but flat. The coast path alternates between flowing stretches, sandy beaches and descents almost to the waterline, with short walls climbing back out. At km 50 comes a kilometre averaging over 15 percent with pitches near 26 percent, and two more steep stings wait shortly before the finish.
Support comes from water points and feed stations placed by the mile, plus a supermarket in Goodwick at mile 24 and public toilets at Abercastle and Abereiddy. The finish sits at mile 53, well past the distance the name promises.
| Start | Length | Ø | Max. | Gain | Cat. |
|---|---|---|---|---|---|
| km 0.2 | 0.9 km | 10.5 % | 19.8 % | +92 m | Cat. 4 |
| km 5.4 | 1.9 km | 6 % | 11.7 % | +114 m | Cat. 4 |
| km 15.8 | 1.2 km | 8.1 % | 14.5 % | +99 m | Cat. 4 |
| km 17.3 | 1 km | 16.9 % | 23.9 % | +165 m | Cat. 3 |
| km 36.5 | 0.9 km | 11.1 % | 24.5 % | +97 m | Cat. 4 |
| km 50.2 | 1.1 km | 15.4 % | 26 % | +162 m | Cat. 3 |
| km 78.5 | 0.5 km | 14.1 % | 22.3 % | +74 m | — |
| km 82.7 | 1.4 km | 8.7 % | 25.1 % | +120 m | Cat. 4 |
Climb categories follow the road-cycling convention and rate the terrain itself (length and gradient) regardless of sport: Cat. 4 marks the easiest rated climbs, Cat. 1 the hardest, and HC (hors catégorie, “beyond categorization”) is reserved for the most brutal ascents. Short climbs below the Cat. 4 threshold stay unrated.
How to pace The Marreg.
Start under control
Plan for 53 miles, not 50. Spread your effort over the number in the name and you reach the last five kilometres with nothing left, which is exactly where two of the day's steepest climbs sit, at km 78.5 and 82.7. The roughly 2,700 metres of climbing come in many short pieces rather than a few long hills, so there is hardly a stretch where you can simply settle in.
Hold your rhythm
The inland opening is the trap. Your legs are fresh, the climbs up to km 20 feel manageable, and the ramp at km 17.3 tempts you to run it. Power-hike it with your heart rate in check, because more than 60 kilometres of coast are still to come.
Spend what is left
The race is decided between km 50 and the finish. On the coast path every drop towards the water costs speed and every climb out costs strength; if you can still run smoothly here, the flowing sections in between give back more time than the whole first quarter.
Training plan for The Marreg: 12-week build
Build the base
For most age-group runners The Marreg is a day of roughly 11 to 16 hours. The effort is mainly aerobic but constantly interrupted by short, steep climbs that push you to threshold if you try to run them. Nearly a third of the course is steeply up or down, and only around ten percent is flat.
Train race pace
The decisive phases come late: the ramp at km 50 and the two stings before the finish arrive only after more than 50 kilometres. So build long runs whose second half is hillier than the first, and put steep repeats of a few minutes at the end of a long session rather than at the start. Strong uphill hiking belongs in the plan as much as running.
Rehearse the course
The surface changes between hill trail, woodland path, sand and coast path. Train on similarly mixed ground, on sand where you can, so that ankles and calves are used to the changes. The many steep descents load the quads; controlled downhill running on tired legs protects you from fading over the final third.
Arrive fresh
The race is held in April, so the build falls in the winter months. Schedule your longest outing a few weeks before race day, and use it to rehearse eating and drinking between aid points that are in places more than ten kilometres apart.
Courses
Download the The Marreg course as a GPX file for your watch or bike computer.
Let YOUB adapt your plan for The Marreg dynamically
Ben connects your goal, the course, current load, recovery, and calendar. Your plan stays pointed at race day even when real life is not perfectly plannable.
Everything about The Marreg.
How long is The Marreg?
The Marreg is 85.3 km long. That distance shapes how much aerobic endurance, pace durability, and race-specific work belong in the training plan.
How much elevation gain does The Marreg have?
The Marreg has around 2,731 m of elevation gain over 85.3 km. That affects pacing, muscular load, and preparation for late-race sections.
What is the route profile of The Marreg?
The Marreg is classified as Mountainous, averaging 31.7 vertical metres per kilometre. 10% of the route is flat, 30% climbs moderately (2 to 6%) and 14% is steeper than 6%.
What climbs does The Marreg have?
The hardest climb of The Marreg starts at kilometre 17.3, runs for 1 km at an average of 16.9% and gains 165 metres. Cycling-convention rating: Cat. 3. 8 climbs are mapped in total.
Is The Marreg a loop course?
No, The Marreg is a point-to-point course: start and finish are in different places.
Is there a GPX file for the The Marreg course?
Yes. The The Marreg course is on this page as a free GPX download — ready to import into Garmin, Wahoo, Komoot, Strava or any other app that reads GPX.
How should I prepare for The Marreg?
Preparation for The Marreg should account for 85.3 km, 2,731 m of elevation gain, current training load, and available training time. An adaptive plan helps place key sessions without ignoring recovery and real life.
What pacing strategy works for The Marreg?
The pacing strategy for The Marreg should reflect 85.3 km, 2,731 m of elevation gain, and your current fitness. Start controlled and keep margin for sections where the profile or fatigue makes target pace harder.
When does The Marreg take place?
The Marreg takes place on April 17, 2027.
Where does The Marreg take place?
The Marreg takes place in Crymych, United Kingdom.
How do I register for The Marreg?
Registration runs through the organiser: narberthnobbler.co.uk. YOUB shows you the course, elevation profile and training plan for your preparation.
