There are two airports located in the San Francisco Bay Area; San Francisco International (SFO) and Oakland International (OAK) with the major international airport being San Francisco International. Both airports have direct links to the city centre (downtown area) via the Bay Area Rapid Transit (BART) system.
Transport from airports into the city
The BART train system runs pretty frequent into the city (every 15-20 minutes) and a one-way ticket can be purchased from the airport for about $9/$10. Once in the city the Muni train system can be used to get around the city.
Alternatively visitors can get into the city via taxi which of course costs considerably more (approximately $40-$50 from SFO and $60-70 from OAK Airport).
As with many big cities Stateside one can get into SF via public coach services such as the Greyhound, Megabus and Bolt Bus. Fisherman’s Wharf ferry dock also welcomes public boats from nearby regions such as Sausalito and Oakland.