You're correct, group lessons start on Mondays, but you can take private lessons starting any day - you'll find the info here: soldeu.com/private-lessons/
My friends and I are coming down to Soldeu to ski 24th to 27th Feb (arriving 23rd leaving 28th). I am the only beginner, never ski'd before, so I know I'll need some lessons. My question is that I've been looking to join ski school but they all start Monday or Saturday. Is it possible to join a group class on the Wednesday? Otherwise what options do I have?
