Chiang Mai City, Thailand · Saturday, November 21, 2026

Fixed Distance 50K

AIA One Billion Trail

52 days away

50 km Distance

2,406 m Climbing

6.1 Grit · Hardcore

18.7904° N, 98.9847° E © OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Climbing rate 48 m / km Mountain. Significant climbing. Steep sections will require power hiking.

Time limit 17 hours 20:24 min/km average. Generous. Walkable throughout for most of the field. Among the most forgiving 50K cut-offs we track. Measured against 1034 races of the same distance. Cut-off calculator →

Field size ~23 Small. Long stretches with nobody in sight.

DUV results for the 2025 edition (50km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, November

Daytime high 25°C

Night low 16°C

Rainfall Mostly dry

Daylight 11 h 11 m of light

Regional 2001-2020 average for November — NASA POWER, grid elevation 759 m. Not a forecast.

Results history

Year	Race	Finishers	Men's winner	Women's winner
2025	50km	23	Jarudech Kengraksat · 04:40:52	Harriet Gaywood · 05:30:52
2024	50km	74	Noppadol Kongkaew · 10:31:01	Thitiporn Titprasaoe · 10:31:01
2023	50km	87	Danon Rattanatumrong · 08:48:45	Kittiya Piyawan · 11:41:24
2022	54.5km	52	Aphichat Jamjaeng · 10:10:27	Chanadda Chananoi · 11:55:03

The field shrank 69% between 2024 (74) and 2025 (23). 22% of the 2025 field were women.

DUV results for the 2025 edition (50km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

The Aid Station

Course-specific beta from the community

⛰️ terrain

This is a mountain course. Poles are highly recommended for the sustained climbs.

By UltraHub Expert

👟 gear

With trail terrain, choose a shoe with moderate cushioning for optimal performance.

By UltraHub Expert

Gear for this race

Chosen for 50 km of trail with 2,406 m of ascent.

Trail Running Shoes 48 m of climb per kilometre — grip and rock protection before cushioning.
Race Nutrition 50 km of self-supported fuelling between aid stations.
Hydration Vests Pole attachment and chest-strap stability on steep ground.
Trekking Poles 2,406 m of ascent to walk up.
Headlamps A 17 h limit puts you out there after dark.

Adidas

Terrex Agravic Speed Ultra

RunRepeat found the Adidas Terrex Agravic Speed Ultra to be perfect for midfoot and forefoot strikers, while iRunFar noted that the shoe feels incredibly effici…

★★★★★ 4.5

La Sportiva

Prodigio Pro

RunRepeat found the La Sportiva Prodigio Pro to have a secure, locked-in fit due to its premium upper, and also praised the shoe's energetic ride, particularly…

$225 ★★★★★ 4.6

Skratch Labs