The gorges around Interlaken are among the best canyoning terrain in Europe, and several operators based in town run trips into them year-round. The standard format involves a guide taking a small group through a canyon: abseiling down waterfalls, jumping into pools, sliding down natural rock chutes polished smooth by centuries of water, and swimming through narrows where the gorge walls close to a metre apart. The combination of glacier-cold water and physical exertion is bracing in a way that stays with you.
The most popular gorges are the Saxeten Bach and the Zütschbach, both within easy reach of Interlaken. The Saxeten is suitable for beginners; the Zütschbach is more technical. A half-day trip takes about four hours including transport; full-day options run deeper into the mountains. The water is cold even in summer — operators provide wetsuits. Book in advance during peak season, and check weather conditions, as heavy rain can make gorges impassable.