Istria 100 by UTMB
Istria 100 by UTMB – 42K
Motovun → Umag
Race guide
Updated 18 July 2026
The Istria 100 by UTMB – 42K is a 42 km point-to-point trail race across the interior of Croatia's Istrian peninsula, starting beneath the medieval hill town of Motovun and finishing on the Adriatic coast at Umag. With 883 m of climbing and a high point of just 380 m, it is the most approachable of the classic Istria distances — a race defined less by any single mountain than by the constant undulation of vineyard hills, oak woods and old stone villages. Because the route runs from the 162 m start down to a coast that sits essentially at sea level, it is a net descent on paper. In practice the profile is deceptive: nearly every checkpoint sits at a different altitude, and the climbs to the hilltop villages come exactly where tired legs least want them. This guide breaks down where the 42K is really decided and how to pace it against the cut-offs.
The Course & Terrain
The 42K travels from Motovun (162 m) to Umag (7 m) with four checkpoints along the way: Livade at 5.1 km, Grožnjan at 20.9 km, Buje at 27.8 km and the finish at Umag at 42 km. This is quintessential inland Istria — a landscape of vineyards, olive groves, oak forest and truffle country stitched together by farm tracks, gravel roads and single trail linking one hilltop settlement to the next. The opening is the fastest part of the day. From Motovun the course drops sharply to Livade at just 17 m, giving away almost all of its early altitude in the first 5 km. From there the race turns into a series of rolling gains and losses across the peninsula, with the standout feature being the long pull up to Grožnjan, perched at 286 m. Underfoot expect a mix of hardpack, gravel and grassy trail rather than technical mountain terrain — fast running that rewards runners who stay light on their feet.
Where the Race Is Won or Lost
The decisive section is the middle third. After the plunge to Livade at 17 m, the course claws its way back up nearly 270 m of net elevation to reach Grožnjan at 286 m by 20.9 km — the biggest sustained climb of the day and the single point where the 883 m of total D+ is most concentrated. Runners who over-commit on the fast descent to Livade often arrive at the foot of this climb with nothing left to give. From Grožnjan the trail drops again to Buje at 153 m (27.8 km), then rolls and descends the final 14 km to the coast at Umag. That closing stretch is where a well-judged race pays off: it is broadly downhill and runnable, so a runner who has kept climbing muscles in reserve can make up real time, while anyone who blew up on the Grožnjan climb will grind through it. Treat Livade-to-Grožnjan as the crux and the Buje-to-Umag descent as the reward.
Pacing & Fuelling to the Cut-offs
The cut-offs tighten steadily toward the coast: Livade closes Sat 13:00, Grožnjan Sat 16:00, Buje Sat 17:30 and the Umag finish Sat 20:00. The gaps between them are generous early and squeeze later, so the plan is to bank a comfortable margin over the first, fast half rather than chase time at the end when the legs are heavier. Aid is spaced roughly 5–16 km apart, with the longest carry being the 15.8 km from Livade to Grožnjan — not coincidentally the hardest climbing of the course. Fill up fully at Livade and carry enough fluid and calories to cover that block, especially in warm conditions. Because none of the four checkpoints is listed as a crew point, plan to be self-sufficient between stations. A steady, even effort that respects the Grožnjan climb will bring most runners home well inside the 20:00 limit.
Conditions to Expect
Istria in late spring can be warm, and much of the 42K runs through open vineyard and farmland with limited tree cover between the wooded sections. With the high point at only 380 m there is no altitude to cool things down, so heat management — fluids, electrolytes and sun protection — matters more than cold-weather kit on this course. The exposed hilltop approaches to Grožnjan and Buje are where the sun bites hardest. The reward for the effort is the character of the route: the start under Motovun's walls, the ridgetop villages, and a finish that trades the peninsula's interior for the Adriatic shoreline at Umag. Underfoot the mixed gravel-and-trail surface stays fast in the dry but can turn greasy after rain, particularly on the descents into Livade and toward the coast — worth factoring into shoe choice if the forecast turns.
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Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-17) · official source
0 km · 162 m · —
5.1 km · 17 m · Sat 13:00
20.9 km · 286 m · Sat 16:00
27.8 km · 153 m · Sat 17:30
42 km · 7 m · Sat 20:00
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