Just wanted to share a local tip. When you get to the top of Matterhorn that takes you to the Italy side there's a tourist trap. The washrooms are charged 2 francs to use and if you turn your ticket you get a bottle of water. So if you're not a fan for paying for the washroom, take the elevator at this stop and on the lower you'll have the washroom . Women washroom has 3 stalls.
Alternatively if you get stuck at the top, just ski down either sides Switzerland or Italy and there are free washrooms.
I really just shake my head to paid washroom, but if you got to go you got to go. Three people in my travel group paid for it while I just patiently waited for the next stop in at restaurant.
Another local tip is bring your own water, every place charges. DM if you have questions :) read more