Originally Posted by
garykung
No. Technically speaking - BART Station is located at an extension from International Terminal G, which is not really considered as a part of the Terminal (Note - BART Station has its own AirTrain stop from ITG).
Technicalities aside, it's a 5-15 minute walk from BART to the security checkpoints of all terminals. The AirTrain (station is directly above BART station) would be a little faster to terminals 1 (Southwest, Delta) and 2 (American, Alaska). Walking at a normal pace is probably faster to terminal 3 (United).