(SFO > BKK) Will I have to go through customs at SFO when transferring to the international terminal?

Question

I'll be traveling from Texas (DFW) to Thailand (BKK) late May this year and had a few questions about transferring from a domestic terminal to international terminal at SFO.

This will be my timeline:
DFW > SFO (American Airlines, will arrive at 10:40pm)
SFO > BKK (Eva Airlines, departs at 1:20am)

Questions:

1. How much time I should budget at SFO to get from Terminal 2 to Terminal G (international terminal)? I will be taking the AirTrain blue line.
2. When will I go through customs and security? Is it as soon as I land in SFO, or before I enter the international terminal (G)?
3. As I'm not a U.S. citizen, should I budget more time to go through customs & security?

Answer 1

1. The AirTrain runs frequently and takes only a few minutes. I would probably allow about 15 minutes to get from Terminal 2 to International Terminal G.

2. You will not go through customs at all; there are no customs or immigrations checks upon exiting the United States. Since the AirTrain is "landside", you will need to re-clear security when you reach International Terminal G. (I am not sure if there is any way to make the transfer while remaining airside, in which case you would not need to go through security at all, but in any case it would mean walking the whole distance instead of taking a train.)

3. You will just be going through regular TSA security, which checks your ID and screens you and your carry-on luggage for dangerous items. It should be the same as the security you clear when boarding at DFW. It has nothing to do with immigration and your nationality will have no effect on how long it takes.

Answer 2

To fill in the unanswered bit: other than the airside hallways from Terminal 3 to the International Terminal and another from half of Terminal 1 to Terminal 2, as mentioned by @Zach Lipton in his Comments above and below, there is no airside transfer between terminals at SFO.

The OP will have to deplane, exit the secure area in Terminal 2, take the AirTrain from Terminal 2 to the International Terminal, then walk into the International Terminal and pass through security again.

Note that there are two departure areas within the International Terminal, one at each end of the large International Terminal main area that has airline check-in counters. Each departure area has its own security lines. Departure information signs will list the OP's flight and direct her to the correct end of the International Terminal.