I do not know many summits which are as broad and flat as a soccer pitch. Sonnenjoch is such a summit. Without the huge summit cross, erected on a massive stone footing you would have a hard time to find the highest point of this summit plateau.
Sonnenjoch is part of the long, south - north running Alpbach - Wildschönau range within Kitzbüheler Alpen. Being the meeting point of the four valleys, Sonnenjoch is separating Wildschönau and Kelchsau / Langer Grund from Alpbachtal and Märzengrund (a tributary valley to Zillertal). Moreover, Sonnenjoch is the center of this range, even though not the highest point.
Being an easy hiking summit in spring, summer and autumn and a rather easy ski tour summit in winter and early spring, Sonnenjoch is one of the better known and therefore more frequently visited summits of the area. Nonetheless you will find your private space on this mountain, given the roomy summit plateau.
Neighbouring summits are Gressenstein and Großer Beil to the north - a nice traverse on a narrow trail - Niederjochkogel and Regenfeldjoch to the south - a more demanding traverse without trails and a bit of nice “Kitzbüheler scrambling” (insiders know what I mean).
Back to soccer on summits. I really do not recommend to try it in reality. One bad aimed cross and you have to look for the ball alternatively
1. at Gressensteinalm (600 m lower)
2. at Erlauer Hütte (1100 m lower)
3. at Gmünderhütte (900 m lower) or
4. at Faulbaumgartenalm (700 m lower).
Main trailheads for Sonnenjoch are:
The general accesses are described on the Kitzbüheler Alpen main page.
Ascent to Gressensteinalm
Sonnenjoch summit panorama
Großer Galtenberg as seen from Sonnenjoch
Torhelm-Kreuzspitze range as seen from Sonnenjoch
Salzachgeier range as seen from Sonnenjoch
Red Tape & Accommodation
There are no restrictions or regulations, as far as I know.
Gressensteinalm provides some drinks and food during the Alm season. Otto - Leixl - Hütte is a private hut, accessible only for members of the possessing alpine club section.
Gear & Mountain Condition
Sonnenjoch can be summited all year round.
In the hiking season you need full hiking gear and good shoes. The summit routes are easy hikes on mostly marked mountain trails and - near the valleys - forest roads. The traverse Sonnenjoch - Gressenstein - Großer Beil does need some easy rock scramble and, with low visibility - a knack for orientation.
The ski routes mainly are easy ones, too. Most routes are beginner routes, maybe with the exception of the west ascent from Otto-Leixl-Hütte to the summit, which is a steeper slope. All ski routes are a treat for the advanced ski mountaineer as well. Sonnenjoch as ski tour can be easily combined with Gressenstein and/or Großer Beil (only eastern ascents from above Gressensteinalm).
Available only antiquarian but an indispensable mountain guide book:
Georg Bleier / Kurt Kettner: Alpenvereinsführer Kitzbüheler Alpen, Bergverlag Rudolf Rother, München, 1984
Horst Höfler, Kurt Kettner: Kitzbüheler Alpen. Mit Skirouten. Führer für Täler, Hütten und Berge, Bergverlag Rudolf Rother, München, 1976
R. Weiss: Skitouren Kitzbüheler Alpen mit angrenzendem Salzburger Anteil am Nationalpark Hohe Tauern, Gebietsführer, Steiger Verlag Innsbruck, 2000 (there is an antiquarian edition from 1985 with only Kitzbüheler Alpen, too)