Istria 100 by UTMB
Istria 100 by UTMB – 69K
Buzet → Umag
Race guide
Updated 19 July 2026
The Istria 100 by UTMB – 69K is a 70 km point-to-point crossing of Croatia's Istrian peninsula, running from the walled hill town of Buzet in the northeast down to the Adriatic at Umag. With 2,186 m of climbing over the distance and a modest high point of 409 m, it sits between the shorter coastal races and the full 100-mile ultra — long enough to demand real endurance, but run on terrain that stays fast and runnable throughout. What makes the 69K distinctive is its shape: it opens by dropping into the low, damp valleys of the Mirna basin — Butoniga at 31 m and Livade at just 17 m — before the real work begins, hauling up to the ridgetop villages of Grožnjan and Buje in the closing third and then descending to the sea. This guide covers where the day is decided and how to manage effort, aid and cut-offs across the peninsula.
The Course & Terrain
From Buzet (77 m) the route runs to Umag (7 m) via five checkpoints: Butoniga at 17.4 km, Livade at 32.2 km, Grožnjan at 48 km, Buje at 54.9 km and the finish at Umag at 69.6 km. The character is classic inland Istria — vineyards, oak woods, truffle country and gravel farm roads linking hilltop stone villages, all on surfaces that favour steady running rather than technical scrambling. The first half is deceptively gentle underfoot but tactically important. The course loses altitude into the Mirna valley, reaching Butoniga at just 31 m and then Livade at 17 m by 32.2 km — nearly halfway, and close to the lowest ground of the whole race. These are flat, fast, low-lying kilometres. Both Buzet and Livade are crew points, making them natural hubs for resupply and a mental reset before the terrain tilts upward in the back half.
Where the Race Is Won or Lost
The crux comes late. Having spent the first 32 km drifting down to the valley floor at Livade (17 m), runners then face the long climb up to Grožnjan at 289 m by 48 km — a gain of roughly 270 m concentrated into the second half, when legs are already 30-plus kilometres deep. This is where the 2,186 m of total climbing makes itself felt and where the field spreads out. From Grožnjan the course drops to Buje at 153 m (54.9 km) and then descends the final 15 km to the coast at Umag. The strategic error to avoid is treating the fast, flat first half as free speed: runners who push too hard through the Mirna valley arrive at the base of the Grožnjan climb with tired legs and pay for it over the last 20 km. Run the valley within yourself, save something for Livade-to-Grožnjan, and the long descent to Umag becomes a place to finish strong rather than survive.
Pacing & Fuelling to the Cut-offs
The cut-offs are Butoniga at Sat 12:30, Livade at Sat 16:00, Grožnjan at Sat 19:30, Buje at Sat 21:00 and the Umag finish at Sat 23:59 — a hard midnight deadline. The tightest squeeze is over the hilly back third, so the sensible plan is to reach Livade (the halfway crew point) with a solid buffer, because the pace inevitably slows once the climbing starts and darkness falls. Aid spacing runs from around 7 km to a longest carry of roughly 15.8 km between Livade and Grožnjan — again matching the hardest climb of the course. Load up at the Livade crew point and carry enough to cover that block plus the pull to Buje. With two crew points at Buzet and Livade, build your resupply and any kit changes around those two stops. A conservative first half and disciplined fuelling through the valley are the difference between a comfortable finish and a scramble against the midnight cut-off.
Conditions to Expect
Because the 69K starts in daylight and pushes toward a near-midnight cut-off, most runners will finish in the dark — a working headtorch and spare batteries are essential for the descents through Grožnjan, Buje and down to the coast. The low-lying Mirna valley around Butoniga and Livade can be humid and, after rain, muddy, so expect the fast valley trail to turn greasy if the weather has been wet. Istria's climate can deliver real warmth by day, and with the high point only 409 m there is no altitude to temper it; the exposed vineyard climbs to the hilltop villages are where heat and sun tell most. Plan for a hot afternoon giving way to a cooler night, manage fluids and electrolytes hard through the middle of the day, and be ready for a temperature swing as the sun drops on the run-in to Umag.
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Checkpoints & cut-offs
✓ Course data verified against the official source (2026-07-17) · official source
0 km · 77 m · —
17.4 km · 31 m · Sat 12:30
32.2 km · 17 m · Sat 16:00
48 km · 289 m · Sat 19:30
54.9 km · 153 m · Sat 21:00
69.6 km · 7 m · Sat 23:59
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