Istria 100 by UTMB® 21K is the 21.5km trail race at Istria 100 by UTMB 2026 (Grožnjan, Croatia). The race starts on April 12, 2026 at 10:00 AM. It starts in Grožnjan and finishes in Umag. The time limit is 4 h.
The course climbs 157m+. With 7m/km of climbing, the course is predominantly runnable. By gradient, 7% of the distance is uphill, 16% downhill and 77% flat. Surface: 53% smooth, 24% trail, and 21% road. Flat-equivalent effort: 21.3 FlatKM.
The course also passes close to Pelegrin (185m) and Starola (165m).
The course is runnable enough that trekking poles are not needed.
There is too little runnable descent to damage the quads: plan the race around climbing and fuelling.
On race day, start temperatures have historically ranged from 8°C to 17°C, with around 13°C at the highest point; the chance of precipitation is about 39%. Heavy rain of 10.0mm or more falls on about 9% of days around this date.
This page has a pacing and nutrition planner, a gradient matrix, an interactive elevation profile and historical weather for Istria 100 by UTMB® 21K.
Other distances of Istria 100 by UTMB 2026Istria 100 by UTMB® 168K (168km)·Istria 100 by UTMB® 110K (111km)·Istria 100 by UTMB® 69K (69.6km)·Istria 100 by UTMB® 42K (42.5km)
Other editions of Istria 100 by UTMB® 21K2027·2025
Official websiteistria.utmb.world
