Public Transportation at San Francisco International Airport include the efficient Metro rail services via BART & Caltrain,  and SamTrans bus.
Note:  Ride-shares by 'Sidecar' (visit: side.cr); and by 'Lyft'  & 'Uber' are now operating at SFO.

By Train:
    BART Rapid Rail
(tel. 510-465-2278 or visit: www.bart.gov)serves directly northern San Mateo County, San Francisco, and the East Bay.  The SFO BART Station is at the International Terminal's Departures/Ticketing level - at  Boarding Area G side.  (If arriving at either Terminals 1, 2 or 3 - take the free inter-terminal AirTrain to Garage G/ Bart Station stop.) 
    Caltrain Commuter Rail:  BART connects the Airport to the Caltrain rail system at Milbrae Station - with Caltrain connections there  to either San Francisco or San Jose.  Caltrain also offers weekday commuter-hour service to Gilroy.  Express trains during commuter hours on weekdays serve only select stations.

By Bus:  For samTrans information, call 1-800-660-4287, or visit www.samtrans.com
    SamTrans Public Buses - Routes KX, 292 & 397
& 398 stop directly at the terminals and run 24/7, serving San Mateo County and parts of San Francisco. SamTrans buses stop at
International Terminal 1: at level 1, Courtyard A, and at curbside next to Courtyard G;
Terminal 2: at Arrivals /Baggage Claim level, at center island next to Courtyard 2;
Terminal 3: at Arrivals /Bagage Claim level, at curbside - adjacent to Courtyard 4.
Also, SamTrans Routes 140, 292 & 397 stop at Rental Car Center - while Routes 292 & 397 stop on North McDonnel Rd. at Airport Business Center & WestField Rd..

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