We alternated between bivouac, campsites and permanent accommodation.
We did not sleep a single night in a refuge, not that we would not have been interested, but because we had to book and that each time we called (in the morning for the evening), they were complete.
We thought we would sleep more in bivouacs, but we were quickly faced with Swiss regulations and the many areas prohibited from bivouacs (not always indicated on the websites of parks and nature reserves).
In addition, we also quickly noticed that the terrain all along the trek really did not allow you to put up your tent. Indeed, between the very narrow path on the mountainside, the path in the undergrowth, the very steep path, the scree areas… you really have to look and be motivated to find a place to bivouac. Even more with a nearby water point. This resulted in us having to walk more than 10 hours on certain days.
You will find information on the bivouac in Switzerland on the Swiss Alpine Club website.
In summary, on this portion of the trek between Zermatt and Chamonix we slept 7 nights in bivouac (including 2 nights in a free cabin), 2 nights in camping and 3 in “hard”.
It is also this alternation that allowed us to keep our spirits up knowing that a hot shower and a good bed were waiting for us, to rest well and to finish the trek in good physical condition.
Even if we never had a problem finding a campsite or accommodation available in August, we must be aware that prices are high in Switzerland, especially at the last minute.