Laguna La Angostura is Cochabamba's easiest lake escape, a reservoir south of the city where locals go for fish lunches, boat rides, and a bit of open water. The setting is not pristine wilderness, but the change from the urban valley is immediate and welcome.
It works best as a half-day outing with a meal by the shore. Go in clear weather, when the surrounding hills and broad sky make the lake feel more expansive, and do not expect solitude on weekends.