Keystone's activities split cleanly between winter and summer. In winter, the three interconnected mountains offer over 3,000 acres of skiing and snowboarding, with Keystone Resort unique among Colorado ski areas for its extensive night skiing. In summer, the same lifts that serve skiers carry mountain bikers, the trails convert to hiking routes, and Lake Dillon becomes the focus for water sports. The two base areas — River Run Village and Keystone Village — serve as the social hubs year-round.
Arapahoe Basin, just a few kilometres up the road, is a worthy companion to Keystone: smaller, steeper, and one of the last Colorado resorts to close each spring.