Lake Brienz stretches east from Interlaken for 14 kilometres, narrower and deeper than Lake Thun, its water a remarkable turquoise-green fed by glacial meltwater from the Haslital valley. The southern shore runs beneath steep forested walls; the northern shore has the road and railway. The overall effect is wilder and less developed than its western counterpart.
The BLS steamboats from Interlaken Ost stop at Iseltwald, Giessbach, and Brienz, where the famous waterfall cascades down through forest to the lake shore — the Belle Époque Grandhotel Giessbach survives there, reached by a historic funicular from the pier. At the lake's eastern end, Brienz is the centre of Swiss woodcarving, with workshops open to visitors and an open-air folk museum nearby. The vintage steam railway from Brienz up to the Rothorn is a separate attraction worth combining with the boat trip.