If you're coming from the Oakland airport, it's not supposed to be too difficult to take a bus to the Oakland Coliseum BART station: Reference.
If you're coming into SFO (San Francisco International), There are a number of ways to get into San Francisco:
- Now you can get directly into the BART system from an airport shuttle train. This is probably the right way to do it.... unless you're coming in on a late flight. There's been some speculation that they might add some late trains on this line to cover the last flights arriving at SFO, but it doesn't look to me like it's happening. As of May 2004, the last weekday train leaves before midnight.
- I used to recommend the KX bus as a good way to travel, but the hours suck now: the last northbound bus is around 11pm. Anyway, if you don't have major amounts of luggage, you can use the Sam Trans KX bus going north (NOTE: this line was formerly called the "7F". Nice to know that management is keeping busy, cutting hours and renaming every route). This is an express bus that only costs a few dollars, and will take you to various points in Soma (starting at 9th street, and going up to around 1st). You can get off at the end of the line on Mission Street, and do a schlep of one long block over to Market street, where you can pick up whatever other transit you need.
- Another method is to use the free shuttle bus to the Milbrae Caltrain station, and take the train north to the last stop: 4th street in Soma, way out on the east edge of town. The N-Judah MUNI trolley line now connects up with the "4th & King" Caltrain station (a big improvement over the really slow bus lines that run by there). You can take the N to any of the stations on Market, or to one of the stops in (or at least near) the Haight, or for that matter you ride it all the way out the the Sunset neighborhood on the west side of town.
- I know it seems like cheating, but if you're only around for a short visit, maybe you're better off taking a shortcut like this: just take a cab to San Francisco. They run something like $30 these days.
There's more transit information down there in the References.