So Swiss service is absolutely terrible.
Booked a code UA (my mistake). Communicated with SwissLurker and the Swiss Media team on FB and was told that online checkin would be available 23 hours before my flight. This is important because codeshare tickets cannot get advanced seat assignments.
Guess what? Information provided by SwissLurker was completely wrong. Codeshares are not eligible for online checkin no matter what time. Your only resource is to wait until 3 hours before the flight and pray to God you got some decent seats.
I tried to checkin at 23 hours, website does not work and has no options for online checkin for codeshares. Called support. Was told to call online checkin support. Phone number is just busy, busy, busy. Finally get through and was told that only recourse is to go to airport. Swiss reps do not even know their own airport service hours. Was told to call SFO directly.
Moral of the story: do not book codeshares with Swiss. If you do, make sure you do not trust anything they tell you.
