Experienced mountaineers can tackle Volcán Llaima from Sector Los Paraguas on the west side of the park, where there is a refugio (rustic shelter) on the road from Cherquenco, or from Captrén on the north side. Although you do not need a climbing permit, you must register your plans with Conaf and sign a release waiving them of responsibility.
It's more orthodox to summit from the Captrén side, where you remain in full view of park rangers the entire route.
The 2008 Volcán Llaima eruption coughed up lava to the southeast into Sector Cherquenco, sparing all of the park's designated trails. One of Chile's finest short hikes, the Sierra Nevada trail (7km, three hours one way) to the base of the Sierra Nevada, leaves from the small parking lot at Playa Linda, at the east end of Laguna Conguillío. Climbing steadily northeast through dense coigüe forests, the trail passes a pair of lake overlooks; from the second and more scenic overlook, you can see solid stands of araucarias beginning to supplant coigües on the ridge top.
Conaf discourages all but the most experienced hikers from going north on the Travesía Río Blanco (5km, five hours one way); a guide is essential.
Near the visitors center, the Sendero Araucarias (0.8km, 45 minutes) meanders through a verdant rainforest. At Laguna Verde, a short trail goes to La Ensenada, a peaceful beach area. The Cañadón Truful-Truful trail (0.8km, 30 minutes) passes through the canyon, where the colorful strata, exposed by the rushing waters of Río Truful-Truful, are a record of Llaima's numerous eruptions. The nearby Los Vertientes trail (0.8km, 30 minutes) leads to an opening among rushing springs.
Centro de Ski Las Araucarias offers skiing on Volcán Llaima.