The normal route to the Sustenhorn leads from the stone glacier and from the Tierberglihütte of the SAC to the summit.
As an alternative, you can climb the Sustenhorn via the east ridge. From the starting point, the Voralphütte of the SAC, to master the 1400 vertical meters in six to seven hours. The difficulty of this combined high tour is given in the SAC high tour guide with ZS. Climbing in mostly good rock (gneiss) moves in III, sometimes in IV.