For 2026, the 57-kilometre S1 Trail is transformed. No longer a line, but a perfect circle. A round trip that starts from the water, explores the Slovenian highlands lashed by the Bora and returns to the sea, in the scenic embrace of PortoPiccolo.
There is something new that will change the face of one of our best-loved races. One of those evolutions that come from listening to the paths and wishes of the runners. For the edition of 4 January 2026, the 57 km distance will become the S1 TransKarst Ultraa spectacular loop route, a total immersion in the soul of the Karst, starting and finishing in the same, magnificent setting of PortoPiccolo.
With 58.55 km and 1814 metres of positive height difference, the TransKarst Ultra was designed to be a condensation of the experience of La Corsa della Bora. Forget shuttles to the start: now the challenge begins and ends at the same point, allowing each participant to experience a complete adventure, a tale that ends exactly where it began.
The Journey: a Tale in Four Acts
Departure at 7:00 a.m. from PortoPiccolo will kick off a journey that is a continuous change of scenery and pace. The first few kilometres are an awakening with breathtaking views, along the cliffs that lead from Sistiana to Duino, until entering the famous Rilke Path. From here, on CAI Path 1, you run along a natural balcony overlooking the Gulf, touching the villages of Santa Croce and passing the first refreshment point at km 8.
Shortly after, the sea leaves behind to enter the most authentic Karst hinterland. It is a plunge into a different world, passing through the Blue Grotto and the Lesa Cave (Grižnica)witnesses to the geological nature of this land. The route becomes history, crossing the Lupinc-Škaljunk Great War Park and reaching the Mount Ermadaa true open-air museum of the Isonzo Front.
The heart of the race is the crossing into Slovenia. Past the second time gate at Prepotto (km 14), we head towards Sela Na Krasuthe highest and most panoramic point of the route. Here, at the 35 km refreshment point, the view sweeps 360 degrees: the Karst, the Gulf of Trieste and, on a clear day, the silhouette of the snow-capped Alps. You run along the front line of the First World War, among trenches and trenches that tell silent stories.
The return to Italy is a return to the flavours and colours of home. The descent towards Medeazza (refreshment stop at km 50) is not just a recovery of energy, but an experience: a true 'race osmic' awaits you here, where the technical refreshments merge with typical Karst products. The last stretch is pure poetry. You take the coast road again, entering the Duino Cliffs Nature Reserve to run, this time in the direction of the finish, the spectacular Rilke Trail. The view of the finish line at the water's edge, down in PortoPiccolo, will accompany you over the last, unforgettable kilometres.
A Race for All
Don't let the numbers scare you. Le 15 hours maximum time make the S1 TransKarst Ultra a challenge accessible not only to the most competitive ultrarunners, but also to well-trained walkers who want to enjoy every single metre of this incredible route, step by step. The time gates are designed to allow steady progression, with refreshments strategically placed to support everyone's effort.
The S1 TransKarst Ultra 2026 is more than a race. It is an invitation to discover the essence of a unique territory, running or walking in a perfect loop between sea, rock and history.
Registration is now open. Are you ready to be part of this new adventure?