American Airlines and British Airways have fares around $560 round trip for San Francisco to Geneva, Switzerland departures from Jan 8-May 11 and Aug 20-Oct 12.
This is the only city in Europe I see on sale from San Francisco with the major alliances for under $600. Rome, London and Stockholm are in mid-$600s.
American Airlines ticket for British Airways operated flights
San Francisco – London LHR – Geneva GVA – London LHR – SFO
$560.76 round trip Sat Feb 4 – Sun Feb 12 (winter ski season)
American Airlines ticket for British Airways operated flights
San Francisco – London LHR – Geneva GVA – London LHR – SFO
$560.76 round trip Sun Aug 20 – Sep 4 (late summer trip)
Loyalty Traveler curated Airfare Deals and Google Flights and Kayak Explore tutorials.
