ROADBOOK

Roadbook S1 Borderless Trail — the route trail by trail

36 km from PortoPiccolo along the Karst ridge: every CAI trail and every race link, in the order you meet them.

The S1 Borderless Trail starts at PortoPiccolo and returns there after about 36 km, with Monte Ermada and the CAI 003 ridge at the centre of the course. This page describes the route in the order you meet it: the CAI trails, the itineraries that run alongside it for a stretch and the race's own connecting links.

From PortoPiccolo to the Sentiero Rilke

The start from the Bora Village at PortoPiccolo is a breathtaking sight: the Adriatic behind you, the white cliffs of the Karst edge ahead. The first stretch is a steep but not technical climb, a natural limestone wall taking you from sea level up to the plateau trails in just a few hundred metres of ascent.

From the Bay of Sistiana the course climbs towards the Sistiana quarry, crosses the wood above the bay and reaches CAI 001, partly shared with the Alpe Adria Trail and, in the cliff sector, with the Sentiero Rilke. They are independent itineraries running here on the same ground: a shared stretch does not make them the same thing.

The Sentiero Rilke is a little over two kilometres suspended between sky and sea along the Duino Cliffs Nature Reserve, between Sistiana/Sesljan and Duino/Devin. It was here, in the winter of 1912, that Rainer Maria Rilke — a guest of Princess Marie von Thurn und Taxis at Duino Castle — heard the first words of the Duino Elegies carried by the wind: «Who, if I cried out, would hear me among the hierarchies of angels?». From these cliffs comes the motto of the Corsa della Bora, being here is glorious.

Duino and the Sentiero del Mitreo

The course follows the Rilke as far as Duino/Devin and crosses the old village in front of Duino Castle, the fifteenth-century residence of the princes of Thurn und Taxis where Dante was a guest before Rilke; beside the ruins of the old castle you can glimpse the White Lady, the rock shaped like a veiled woman.

From Duino the course takes CAI 001a — Sentiero del Mitreo. At the Mithraeum Cave, or Mithraeum of Duino, it leaves CAI 001a and takes CAI 033. Shortly afterwards comes the first race fork: the S1 Family Hike & Trail takes its own shorter loop, while the S1 Half Trail, S1 Borderless Trail, S1 TransKarst Ultra and S1 Bora Ultra continue on CAI 033.

Towards Medeazza

Beyond Duino the terrain changes character: you leave the coastal cliffs and enter the plateau, where Monte Ermada — Grmada in Slovenian, 323 metres — dominates the landscape like a sentinel between two worlds. The climb is gentle and steady through mixed pine and beech woods; its slopes still hide First World War trenches and fortifications.

The course continues on CAI 033 and then moves to CAI 003a, which leads to Medeazza/Medjavas, a village of stone houses where the Italian Karst looks towards Slovenia. Here, at around km 9.8, comes the big race fork: the S1 TransKarst Ultra and the S1 Bora Ultra take the long branch towards Jamiano, while the S1 Borderless Trail stays with the S1 Half Trail and turns towards Monte Ermada.

The cross-border sector of Monte Ermada

From Medeazza the course takes CAI 003 — Alta Via del Carso and crosses the cross-border sector of Monte Ermada/Grmada, passing through the area of the Jastreb summit, the Grofova jama — the Fire Cave, also known as Vogenca — and the Grotta 1ª a nord del Monte Querceto.

After the Sixth Battle of the Isonzo, in 1916, the Austro-Hungarians, having withdrawn from the heights above Monfalcone, made Ermada the defensive pivot controlling the Brestovizza valley and the routes towards Trieste. Today the mountain is an open-air museum — trenches, cave shelters, artillery emplacements and observation posts — and a stop on the Walk of Peace/Pot miru, the cross-border memorial itinerary linking over three hundred First World War sites between Italy and Slovenia, from the Alps to the Adriatic; the Walk of Peace documents its positions and hiking loops. The Grofova jama is a richly concretioned cavity where Austro-Hungarian engineers built terraces and sleeping places for the troops.

The Grotta del Motore: here the Borderless carries on

The course reaches the Grotta del Motore, also known as the Cavern of Monte Querceto. This is the fork with the S1 Half Trail, at around km 13.2: while the Half leaves CAI 003 to climb to the summit of Ermada, the S1 Borderless Trail carries on eastwards on CAI 003.

The route passes close to the Grotta Dörfler, where the natural part of the cavity opens into a tunnel dug during the First World War to connect two dolines and shelter the troops. It then passes Monte Sambuco/Bezgonov vrh and, immediately afterwards, at around km 15.6, merges again with the S1 TransKarst Ultra and the S1 Bora Ultra, sharing their way back.

The shared way back: Precenico, San Pelagio and the Lupinc Park

From the merging point the course follows CAI 003 to CAI 032, which leads through the Precenico area to San Pelagio/Šempolaj. Between San Pelagio, Prepotto/Praprot and the Fornace di Aurisina the route alternates local links, a short stretch of CAI 010, the non-CAI passage through the Lupinc Park, a stretch of CAI 035 and a link near the Fornace and the SP 5, before picking up CAI 010 again towards Santa Croce/Križ. The name Sentiero Gemina should not be used as a synonym for CAI 010: in the CAI register the Sentiero Gemina is CAI 042.

The Lupinc Great War Park is an open-air museum created by Danilo Lupinc on his own land for the centenary of the First World War: trenches dug into the limestone by Russian prisoners of war in the service of the Austro-Hungarian army, a plaque dedicated to his grandfather Anton Terčon, who fell in 1916, and the Grotta Lesa, a natural doline with a collapsed roof reached through a stone arch.

Santa Croce and the finale by the sea

Leaving the Lupinc Park, the course drops towards the sea: the horizon opens onto the Adriatic all the way to Santa Croce/Križ, once a village of Slovenian fishermen who climbed up from the coast along the Sentiero della Salvia to spot the tuna shoals in the Gulf of Trieste/Tržaški zaliv. From here on, the final part is the most runnable of the whole race.

From Santa Croce the course uses stretches of CAI 001 and coastal and educational links, then short fragments of CAI 023 — Sentiero Tiziana Weiss, named after the Triestine climber who died at 26 in 1978 on the Pale di San Martino. The trail runs level, raised above the sea, to the Vedetta Weiss, a panoramic terrace 159 metres above sea level with a bunker of the Gladio network at its foot. The final kilometres touch the Costa dei Barbari, cliffs plunging into the water, before the last plunge down to the Bora Village at PortoPiccolo.

Technical sequence

CAI 001 / Sentiero Rilke → CAI 001a → CAI 033 → CAI 003a → CAI 003 → Grotta Dörfler → Monte Sambuco → merge with S1 TransKarst Ultra and S1 Bora Ultra → CAI 032 → links → short CAI 010 → Lupinc Park (non-CAI) → CAI 035 → Fornace/SP 5 link → CAI 010 → CAI 001 and links → short sections of CAI 023 → PortoPiccolo

The race forks

The distances starting from PortoPiccolo share the opening kilometres and split at precise points, verified on the official 2027 tracks.

S1 Family Hike & Trail / S1 Half Trail — split shortly after the Mithraeum, at around km 7.75; the two tracks meet again at about km 8.36 of the S1 Family Hike & Trail, which corresponds to about km 16.90 of the S1 Half Trail.
S1 TransKarst Ultra and S1 Bora Ultra / S1 Half Trail and S1 Borderless Trail — split at Medeazza, at around km 9.8 of the races starting from PortoPiccolo.
S1 Half Trail / S1 Borderless Trail — split at the Grotta del Motore, at around km 13.2.
S1 Borderless Trail / S1 TransKarst Ultra and S1 Bora Ultra — they merge again just after Monte Sambuco, at about km 15.6 of the S1 Borderless Trail and about km 34.8 of the S1 TransKarst Ultra.