Only 18km west of San Juan, the 32-sq-km Dique Ullum is a center for nautical sports: swimming, fishing, kayaking, waterskiing and windsurfing (though no rental equipment is available). Balnearios (beach clubs) line its shores, and hanging out for a day in the sun is part of being in San Juan. At night, many of the balnearios function as dance clubs.

Bus 23 from Av Salta and bus 29 from the San Juan bus terminal via Av Córdoba both go hourly to the dam outlet.