Istria 100 by UTMB, live.

Every course ends on the sea in Umag

Five races start in five different places across the Istrian peninsula, and all of them run west to the same finish on the coast at Umag.

Istria 100 by UTMB started in 2013 and now gathers more than 3,000 runners. The 2027 event runs 1–4 April. The 168K leaves the old town of Labin on the east coast at 17:00 on Friday 2 April, climbs Učka — the highest point of the course — and comes down through the Ćićarija range to Buzet, the largest aid station and the drop-bag point. On Saturday 3 April the 110K (07:00) and 69K (09:00) start in Buzet and the 42K (12:00) at the foot of Motovun; the 21K leaves Grožnjan at 10:00 on Sunday 4 April.

From Buzet westward the courses share the Istrian interior: hill towns such as Motovun, Oprtalj, Završje and Grožnjan, Butoniga lake, deep forest, an old railway line, streams and muddy valleys, before the last kilometres run to the seafront. The organiser is blunt that the 168K is harder than its profile suggests — 168 km, 6,800 m of climbing and a 45-hour limit on technical ground — while the 21K, with 157 m of climbing, is meant for newcomers to trail.

With staggered starts over three days, families waiting in Umag are watching runners coming from very different distances at once. On Livebib the runner shares one link; family and friends open it in a browser, with no account and no app, and see the position on the course line, the distance covered and a finish estimate that updates as the race goes. In the forests under Učka at night, or in a valley with no signal, the position is carried forward along the course and marked as estimated instead of freezing.