Reñaca is the most famous beach in the Viña del Mar area — a long crescent of sand a few kilometres north of the city centre, backed by apartment towers and a strip of bars, restaurants, and beach clubs. In January and February it is packed, loud, and very social, with a crowd that skews young. The water is cold (Humboldt Current cold — count on 14–16°C even in summer) but that does not seem to discourage anyone.
Getting here from central Viña is easy by local bus or colectivo. The beach fills from mid-morning and the bars stay busy until late. Weekends in high season bring the densest crowds; if you want to find space on the sand, go early or go on a weekday. Out of season, Reñaca quiets down considerably and some of the beach businesses close entirely.