United Airlines and Star Alliance have low fares around $379 to $387 and low $400s for San Francisco and San Jose flights to Barcelona, Spain for travel August 11 to October 18, 2017.
This low fare is an addition to comparable ticket prices for Amsterdam, Brussels, Rome, Venice and Zurich for August to March 2018 travel.
Loyalty Traveler – SFO/SJC fare war to Europe $379-$443 AMS, BRU, FCO, VCE, ZRH Aug-Mar 2018 (May 10, 2017).
United Airlines San Jose SJC – Chicago ORD – Montreal YUL – Barcelona BCN – Newark EWR – San Jose SJC
Lufthansa Airlines San Francisco SFO – Frankfurt FRA – Barcelona BCN – Frankfurt FRA – San Francisco SFO