The Tour du Mont Blanc is one of the great long-distance walks in Europe, and Courmayeur sits almost exactly at its halfway point on the Italian side. The trail circumnavigates the entire Mont Blanc massif over roughly 170 kilometres, passing through the French, Italian, and Swiss Alps in a loop that can be completed in seven to ten days. Courmayeur is the natural place to rest, resupply, and, if necessary, bail out or begin the circuit.
Even if you are not doing the full tour, the sections closest to Courmayeur offer outstanding day hiking. The path over the Grand Col Ferret from the Val Ferret into Switzerland is a full day with serious ascent and extraordinary views. The descent into the Val Veny from the Col de la Seigne is another classic. The town has a good network of marked trails, and the tourist office can provide maps and current conditions. In summer, the trails at higher altitude can be icy until late June.