Chapelco is the local ski area and the main reason San Martín stays busy in winter. The mountain has a broad mix of runs, forested slopes, and views that remind you this is still Patagonia, not a sealed-off resort bubble.
Outside ski season, the access road and surrounding hills are still useful for views and mountain air. Check lift and road conditions before going; weather on the ridge can be very different from the calm lakefront in town.