To get to San Pedro de Atacama from Santiago, you can take a flight to the Calama International Airport and from there take a bus or transfer that takes about 1 hour and a half to get to the town.
It is also possible to arrive in your own vehicle, since San Pedro de Atacama is located about 1,600 km north of Santiago, following Route 5 North and then taking Route CH-23.
Another option is to take a bus from Santiago to Calama and then take a transfer or bus to San Pedro de Atacama.
See more about the location of San Pedro de Atacama
See also information on Calama.