Ultra-Trail Snowdonia by UTMB®
Ultra-Trail Snowdonia by UTMB® – UTS 50K
Llanberis
Race guide
Updated 18 July 2026
The UTS 50K is the middle-distance mountain race at Ultra-Trail Snowdonia by UTMB, a 56 km loop from Llanberis carrying 3255 m of positive climbing and a high point of 1065 m. At roughly 58 m of ascent per kilometre it is, if anything, even denser in vertical than its longer siblings, and it climbs higher than the UTS 100K does. This is not a stepping-stone 50K; it is a full serving of what makes Ultra-Trail Snowdonia so brutal. Like the other UTS distances, the course drops its checkpoints low in the valleys of Eryri (Snowdonia) while the climbing stacks up in between. From the 105 m start in Llanberis you are pulled up toward the 1065 m high point and back down to valley-floor aid stations more than once, on steep, technical Welsh mountain trail. A tight sequence of cut-offs keeps the pressure on from the first checkpoint to the finish.
The course: a high, steep loop from Llanberis
The UTS 50K starts and finishes in Llanberis at 105 m over a 56 km loop. Its three intermediate checkpoints sit low: Gwastadanas Farm at 15.3 km (79 m), Bron Y Fedw Uchaf at 32.9 km (151 m), and Betws Garmon at 41 km (128 m), before the return to Llanberis at 56 km. Against those low aid points stands a high point of 1065 m, so the 3255 m of total climbing is concentrated into the legs between the stations rather than spread evenly. That structure defines how the race feels. The long opening leg of about 15 km to Gwastadanas Farm and the roughly 18 km stretch from there to Bron Y Fedw Uchaf are where the big climbs live, taking you high above the valley and back down again to reach support. Because Llanberis start and finish share almost the same altitude, everything you climb must be surrendered, making controlled descending as important as strong climbing on this loop.
Where the race is won or lost
The decisive terrain is the high ground reached between the low checkpoints, up toward the 1065 m top. Reaching that height from valley-floor aid stations means sustained, steep ascents that are almost always faster to hike than to run, followed by descents severe enough to shred unprepared quads. The middle of the course, across the long leg to Bron Y Fedw Uchaf at 32.9 km, is where a day built on early over-effort tends to come apart. The final leg from Betws Garmon at 41 km (128 m) back to Llanberis at 56 km (105 m) is a substantial 15 km closer that still involves climbing before the drop into town. After 41 km on this kind of gradient, tired legs are tested one more time. Runners who paced the first two legs with discipline and kept their descending controlled will be able to push here, while those who chased time early will be reduced to a grind. Save something specific for this closing section.
How to pace and fuel it
The cut-offs frame the whole effort: Gwastadanas Farm by Sat 12:45, Bron Y Fedw Uchaf by Sat 16:45, Betws Garmon by Sat 19:00, and the Llanberis finish by Sat 23:00. They are set for steady, sustainable mountain running rather than speed, so measure your progress against them at each checkpoint. If the first barrier at Gwastadanas Farm feels tight, treat it as an early warning that the terrain is outpacing your plan and rein the effort in before the later, unforgiving gaps. With only three intermediate aid stations across 56 km, the carries are long: about 15 km to Gwastadanas Farm and roughly 18 km on to Bron Y Fedw Uchaf. Leave each station with enough fluid and calories to cover a major climb, because there is no support in between and 3255 m of ascent burns through reserves fast. Eat early and often rather than waiting for hunger, and use the aid stations to top up properly so a fueling gap never compounds the physical demands of the climbs.
Conditions to expect in Eryri
The UTS 50K tops out at 1065 m, higher than the UTS 100K, and Eryri (Snowdonia) weather at that altitude can shift fast and independently of the valley forecast. Expect a real contrast between sheltered, low checkpoints such as Gwastadanas Farm (79 m) and Betws Garmon (128 m) and the cold, wind-exposed high ground near the 1065 m top. Carry adjustable layers and be ready for conditions up high to be markedly more serious than at the Llanberis start. The steepness that produces 3255 m of climbing in 56 km comes with rocky, technical, frequently wet trail that is slow to ascend and demanding to descend. With the finish cut-off at Sat 23:00, slower runners may face fading light near the end, so carry a headtorch even if you expect to finish before dark. Choose shoes with strong grip, stay deliberate on the long descents back toward Llanberis, and approach the loop with patience: on a UTS course, steady climbing and careful footwork beat early aggression.
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Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-17) · official source
0 km · 105 m · —
15.3 km · 79 m · Sat 12:45
32.9 km · 151 m · Sat 16:45
41 km · 128 m · Sat 19:00
56 km · 105 m · Sat 23:00
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