Your description of the international arrival flow is correct. Passengers go upstairs and walk around a big empty area that I presume was originally intended to house the immigration (passport control) desks. There are also restrooms in this area. But since SAN implemented a different passenger flow, passengers just continue back down the escalators to the ground level where baggage claim and the Global Entry kiosks are located. Once passengers have claimed checked bags they proceed to the desks where an officer performs both customs and immigration functions.
Thank you for the update! Ironically enough, despite my so-called "SAN credentials", I have never utilized my own beloved airport's new international facilities. My one and only arrival to SAN internationally was July 2, 2017, on Edelweiss Air, in the final days of that facility's use.
As the US does not have any form of exit passport controls there is no separate international departure area. International departures use the same waiting areas in Terminal 2 as domestic passengers.
Again, thank you - this one I should have known, but my experiences for international flights are all almost entirely from LAX International Terminal (TBIT), with Mexicana in 1998 and Lufthansa in 2017. No international departures yet from SAN!
Question for those in the know, as it relates here: at HNL airport: In 2009, I flew HA SAN-HNL-ITO, and the return flight to SAN ended up departing from Gate 25. This particular gate at HNL, unlike all the others, was not "open-air" - in fact, not only was this an enclosed room, but to enter the waiting area one had to show the boarding pass! Then behind us, the sliding doors closed, and we waited there until our flight boarded. For domestic flights, why would this have been necessary? And for an international flight, why would this have been necessary? SAN had the same kind of set-up at Gate 21, just upon entry passed security for T2E.
But back to my rambling: with all this talk of the international facilities at SAN, it is ironic that my next "dreaming-of-but-on-hold" trip to Europe will, again, start at LAX, solely to fly on an A380. Assuming there are any flying to Europe after this quarantine is over - who knows? However, my trips always end with a return into SAN, as the going portion of the trip is when we're most excited, so a train trip to Union Station and the FlyAway bus adds to the fun - but when the trip is over, it's wonderful to see Balboa Park upon landing, and realize that I will be home within an hour. And given what planes we will probably never see at SAN, like the A380 or A350, I might not ever in my lifetime depart internationally from SAN!!
Hawaiian being collocated with Delta may also be an artifact of that they used to be handled by Delta. By 2002 they were but prior to that they were handled by Northwest, with the check in counter next to Northwest in T2 East and used Gate 22 (yes, they could fit a DC-10 in the corner). When they switched to Delta they moved to T2 West and stated parking at the half-rotunda at the end of T2 West before the Geeen Build created the western half of the concourse.
Again, outstanding research and knowledge! I do remember seeing Hawaiian DC-10's at T2E, but it seems I might have seen Hawaiian utilizing Gate 21 and/or Gate 24 (each on the opposite side of Gate 22). Is this a true statement?
And might there be a definitive list somewhere of what gates have/can park a wide-body? I know most wide-body service is going to be international; however, Delta has never NOT had something rotating to/from ATL at some point, and in the glory days of domestic wide-bodies, SAN got its share.