During his stay in Bern, Wyss-Dunant climbed all the main summits of the Bernese Oberland: among the classic routes in his record at that time were the Mittellegi Ridge of the Eiger, the North Ridge of the Mönch and many good ascents in the chain of the Grosses Engelhorn. In his early twenties, he traversed the Dent d'Hérens from the Tiefenmatten-Joch to the Col du Lion and made a double traverse, in two days, of both the Matterhorn and the Dent d'Hérens. He also achieved a solo traverse of the Matterhorn and climbed it by its formidable Furggen-Grat with Alexander Taugwalder. He also climbed extensively in the Mont Blanc massif with Marcel Kurz.