I was quite astonished that there was no description of the ascent to Dreiländerspitze from Switzerland - not an uncommon route - so I will contribute to that because I did this route in august 2006 after having summited Piz Buin the day before.
The southern route to Dreiländerspitze starts at Chamonna Tuoi (Tuoi alpine club hut) in the Unterengadin valley, Switzerland. The route ascends to the Fuorcla Vermunt, crosses the swiss / austrian border and after a glacier traverse follows the normal route from Austria, Wiesbadener Hütte.
To get to Chamonna Tuoi, a nice hut of the swiss alpine club with a very friendly staff, you best start at the village of Guarda.
To get there, take road number 184 from Landeck / Inntal valley (exit the highway A 12 at Landeck; toll road) to the austrian / swiss border and the swiss road number 27 to Ardez and the intersection to Guarda.
From the direction of Sankt Moritz or Chur take the road number 27 likewise to the intersection to Guarda after the village of Lavin.
From Rhine valley and Davos / Switzerland, you can choose the Flüela pass road number 28 to Lavin and Guarda.
From Italy / Vinschgau valley, take road number SS 40 and SS 41 to the italian / swiss border and road number 28 via Ofenpass to Zernez, Lavin and Guarda.
Some 200 m before entering the village of Guarda there is a parking area (1581 m, fee required) where you must leave the car. It is the parking area for visiting this old and beautiful Engadin village with all those “sgraffitto houses" (don´t miss that !!) and for the trailhead to Chamanna Tuoi.
Follow the signposts to Chamonna Tuoi. You enter the valley of the La Clozza creek on a forest road. At a switchback of the road a trail starts, leaving the road on its right. Follow the trail, crossing the creek and leading up a meadow ridge (Salön) which overcomes a glacial terrace and leads you into the upper Tuoi valley. The trail gently ascends through meadows and light woods and reaches the Alp Suot.
From the Alp follow the forest road further into Tuoi valley. Piz Buin stands towering above the end of the valley. The road leads directly to the Chamonna (2250 m), where the friendly staff is waiting with a welcome drink for you.
From Chamonna Tuoi follow the marked trail to the north. It zigzags up the steep south slope above Chamonna Tuoi and reaches the point 2608 m of the swiss topo map. At this point you enter a little alpine valley below Fuorcla Vermunt. The trail traverses the east slope of this valley through moraine scree and debris and enters the little ice and snow field below Fuorcla Vermunt.
Fuorcla Vermunt is nowadays icefree. There is the old border guard hut and a sign to show the swiss / austrian border. I don´t think there will be any border controls.
Traverse Fuorcla Vermunt and enter the Vermunt glacier on the austrian side. After a little descent leave the glacier track leading down to Wiesbadener Hütte and traverse the Vermunt glacier to the northeast, passing below the beginning of the rocky west ridge of Dreiländerspitze. The route now starts climbing up the glacier more steeply in the direction of the visible summit. Soon you will join the glacier ascent from Wiesbadener Hütte. The now united tracks lead up to the west ridge where a nice rock climb through short chutes, slabs, ledges and rocky steps starts. It is UIAA grade I and maybe II to II-, a little bit exposed and quite entertaining. With ice and snow it will be a lot more difficult !
The scramble ends at the exposed summit ridge. The summit with the cross is a bold and daring rock spire; you have to traverse a notch and climb this spire on its north ridge (UIAA grade II for shure).
Great views are waiting for you!
Essential Gear, Mountain Conditions
You need full glacier gear, rope, ice axe and crampons.
You need experience with glaciers and a little rock climbing experience.
Mountaineers do the traverse from Chamonna Tuoi to Wiesbadener Hütte (or vice versa) and tackle Piz Buin on the next day on their way back to their starting point. This is a very nice 2,5 days round trip in the Silvretta group.
Dreiländerspitze south route is surely a summer and autumn hike. It can be done - I think - as a ski hike in winter, too.
There are several good maps available for the region:
Landeskarte der Schweiz, 1 : 50.000
Zusammensetzung Unterengadin / Engiandina Bassa
Bundesamt für Landestopographie 3084 Wabern
Landeskarte der Schweiz, 1 : 25.000
Blätter 1198, Silvretta and 1199, Scuol
Bundesamt für Landestopographie 3084 Wabern
Alpenvereinskarte 1 : 25.000
Blatt 26, Silvrettagruppe
This one covers not the part from Guarda to Alp Suot but Chamonna Tuoi and the whole ascent is on this map.
For the weather forecast see this link.
For avalange bulletin click here.
Chamonna Tuoi - SAC
Wiesbadener Hütte - ÖAV
Silvrettahütte - SAC