Slovenia · Carinthia (Koroška)
Distance
50 km
Date
Entry fee
€80
€ / km
€1.60
New date pending
This race has already occurred. A new date for next year’s edition is pending.
K24 Ultra-Trail 50km traces 50 kilometres through the Karawanken mountains of Slovenia's Koroška (Carinthia) region, based out of the former mining town of Črna na Koroškem. With 2,550m of D+ — officially confirmed on the race website at 51m per kilometre — the course ranks 94th most mountainous out of 390 European ultras: only 93 races carry more mountainous terrain. The biggest single descent drops 645m at an average gradient of −8.7%, ranking 92nd most dramatic in the database.
Public transport is limited and accommodation in Črna books quickly — a car and advance planning are both essential. Entry is uncomplicated: €80 for 2026 with no hidden fees, and the race has no sell-out history at this distance. First staged in 2019, the K24 is a cult fixture in the Slovenian mountain running calendar, listed on ITRA and drawing runners to one of the least-touristed mountain corners of the Eastern Alps. Three airport options — Ljubljana, Klagenfurt, Trieste — within 1–2.5 hours serve international access.
Total Meters
2,550m
D+/KM
51.0m/km
For context, the Tor des Géants 330 loop has 73 D+/km.
Avg Uphill Gradient
14.3%
Avg Downhill Gradient
-12.6%
| 2–5% | 4.6 km | |
|---|---|---|
| 5–10% | 3.9 km | |
| 10–15% | 3.6 km | |
| 15–20% | 2.3 km | |
| 20%+ | 4.8 km |
| 40.2% | Uphill |
|---|---|
| 14.4% | Flat |
| 45.4% | Downhill |
| 1 | 3.6 km · 645 m gain starts km 29 · avg 17.9% · max 48.1% |
|---|---|
| 2 | 3.9 km · 591 m gain starts km 0 · avg 15.0% · max 52.2% |
| 3 | 5.8 km · 504 m gain starts km 6 · avg 8.8% · max 33.3% |
| 1 | 9.2 km · 1,111 m drop starts km 33 · avg -12.1% · max -70.1% |
|---|---|
| 2 | 4.7 km · 409 m drop starts km 14 · avg -8.7% · max -43.1% |
| 3 | 2.9 km · 361 m drop starts km 44 · avg -12.0% · max -48.2% |
The official race website confirms 2,550 meters of elevation gain over a 50km distance, averaging 51 meters of climbing per kilometer, a figure verified by exact GPX data matching. The course ranks 94th most mountainous out of 390 European ultras and 139th in vertical density. The GPX file measures the course slightly shorter at 47.79km, the official 2,550m in elevation gain is official and used for all rankings.
K24 Ultra-Trail is based in Črna na Koroškem, a small town in Slovenia's Koroška (Carinthia) region. Public transport is limited — a car is strongly recommended. The three nearest airports are Ljubljana (LJU), Klagenfurt (KLU, Austria), and Trieste (TRS, Italy), all approximately 1–2.5 hours away. Accommodation in Črna is limited; book early, and consider Slovenj Gradec (~25km) as an alternative base.
Very hard by the data. The course ranks 94th most mountainous out of 390 European ultras. The biggest single descent drops 645m at an average gradient of −8.74%. Average uphill gradient ranks 107th steepest. With only 15% flat terrain and 2,550m of elevation gain in 50km, this is a technically demanding alpine race — not a beginner ultra. The course demands both uphill endurance and technical downhill skill.
No — the K24 50km has no sell-out history at this distance. Entry for 2026 is €80 (January 1 to May 31, 2026) with no hidden administrative fees. Registration is via https://k24trail.si/en/proge/k24-trail-50km-en/. The race is ITRA certified and first held in 2019. Both entry tiers for 2026 may be expired as of race week (August 2026) — verify current registration status directly with the organiser. For 2026, early bird fee is at €70 (October 1, 2025-December 31, 2025), regular prices at €80 (January 1, 2026-May 31 2026), last minute registration fee €90 (June 1, 2026-July 31, 2026).
K24 Ultra Trail 50km runs during the day from 07:00–21:00 window with a given 14hr cutoff rather than overnight like the 100km, runners will spend more time exposed to full daytime August heat at valley/mid elevations, with the Smrekovec high sections offering some relief. Valley daytime temps typically 22–28°C in early August; cooler and more volatile at altitude (Smrekovec summit ~1,577m). Be aware that in the afternoon, thunderstorms are a recurring risk in the Slovenian Alps/pre-Alps during summer.
Nearest airport
Ljubljana (LJU) / Klagenfurt (KLU) / Trieste (TRS)
Notes
Start: ~1.0–2.5 hrs to Črna na Koroškem area / Public transport: limited; buses to Slovenj Gradec/Ravne + taxi last-mile; car recommended / Accommodation: limited in Črna; book early; alternative base in Slovenj Gradec
Ibiza Trail Maratón 48 km
Exclusive Discount - use ITMF-DISCOVERTRAIL26 CODE for 50% at checkout
