Should I size AT boots differently than my alpine boots?

Many experienced AT skiers opt for the same mondo size as their alpine boots but with slightly more volume in the forefoot, or they rely on heat-moldable liners to fine-tune the fit. Feet tend to swell during long tours, so a boot that's perfect in the parking lot may feel tight at the summit. However, you still need secure heel hold for the descent. The best approach is to get professionally fitted with the socks you'll tour in, and err on the side of a snug fit that can be customized through liner molding rather than sizing up.