The major gateway to San Francisco is San Francisco International Airport (SFO), 15 miles south of the city. Flight time to San Francisco is 11 hours from London, 5½ hours from New York, 9½ hours from Tokyo, and 13½ hours from Sydney.
A taxi ride from SFO to downtown costs around USD 60; rideshare companies like Lyft and Uber are a popular option and start at USD 25 for a shared ride into the city. Airport shuttles are inexpensive and generally efficient. Lorrie's Airport Service and SuperShuttle both stop at the lower level near baggage claim and take you anywhere within the city limits of San Francisco. The fee is ca. USD 17 each way, depending upon the destination. Lorrie's also sells tickets online; you can print them out before leaving home.
BART rapid transit also goes directly to downtown San Francisco; the trip takes about 30 minutes and costs less than USD 9. There are both manned booths and vending machines for ticket purchases. Trains leave from the international terminal every 15 or 20 minutes, depending on the day and time. You can exit at Embarcadero Station and get a taxi from the nearby Hyatt Hotel to the Presidio venue, which is somewhat less expensive than a taxi all the way form the airport.