To get to Reñaca from Santiago de Chile, you can take a bus from the Santiago Bus Terminal to Viña del Mar, which takes approximately 1 hour and 30 minutes.
Then, from Viña del Mar, you can take a taxi or minibus to Reñaca, which is about 15 minutes away.
You can also get there by your own or rented car, taking Route 68 until you reach Viña del Mar, and then continuing along Avenida Borgoño towards Reñaca.
See also information on Santiago de Chile y Viña del Mar.