I only used these for about an hour for a walk around the neighborhood, not for mountain climbing, and have been storing them at home since. I would buy a size 23 or 23.5. When I try them on barefoot, they're a little big, but I think I can adjust them with the laces. I'm not familiar with mountain climbing, so I don't know much about it, but I think they would probably fit well with thick socks. Maybe someone who wears a 23.5 to 24 cm size would be best. Please use these if you're going outdoors this fall for the leisure season. They will be shipped without the box. Gore-Tex Vibram sole