About
CORE X250 Ultra Trail - 250K is a 249 km ultra race with 13,665m elevation gain in Thailand. Terrain: mountain, forest. Near Doi Luang Chiang Dao National Park. Rated herculean difficulty. Located near Chiang Dao, Chiang Mai.
Organized byCORE THAILAND
Difficulty
Herculean385 KE
KM-Effort = distance (km) +elevation gain (m)100
Based on the ITRA standard.
Elevation Density55 m/km · Hard
Elevation Density =elevation gain (m)distance (km)
Time limit:98h
Run Conditions
MountainForest
Weather in Dec
Temperature
17 – 27°C
Warm
Humidity
Very high
Rainfall
19 mm
Dry season
Sunshine
10.6h/day
~2 rainy days expected
Registration
Deadline
Not specified
Entry fee
Early Bird – 5,900 THB(~$180)until Apr 5, 2026
Regular – 6,800 THB(~$207)
Travel & Logistics
VenueChiang Dao Scout Camp (ค่ายลูกเสือ อ.เชียงดาว)
Google MapsView on Maps
Nearest airports
CNX - Chiang Mai International Airport120 km | ~2h24 driving time
CEI - Mae Fah Luang-Chiang Rai International Airport215 km | ~4h18 driving time
Race Day Info
GPX File
Not yet released, check again closer to race date
BiB Collection
Not available yet, check again closer to race date
Mandatory Gear
- GPS device
- Map
- Compass
- Altimeter
Other Distances
CORE X250 Ultra Trail - 15K
16.3 km+485mDec 23
ITRA
CORE X250 Ultra Trail - 30K
34.5 km+1,846mDec 23
ITRA
CORE X250 Ultra Trail - 50K
53.4 km+2,704mDec 23
ITRA
CORE X250 Ultra Trail - 70K
70.5 km+4,112mDec 23
ITRA
CORE X250 Ultra Trail - 100K
106 km+5,905mDec 23
ITRA
CORE X250 Ultra Trail - 161K
174 km+9,269mDec 23
Community
Reviews
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Race data is actively being refined. If something looks off, .
Sources: website · Enriched 2026-05-29