American Airlines has San Francisco SFO to Brussels BRU priced at $424 to $442 round trip and San Jose SJC to Brussels at $446 for travel from mid-August to late October. Ticket prices are about $100 more for travel November to March.
American Airlines San Francisco SFO – Helsinki HEL – Brussels BRU – London LHR – San Francisco SFO
$423.56 round trip Tue Aug 22 – Wed Aug 30
American Airlines San Jose SJC – Phoenix PHX – London LHR – Brussels BRU – London LHR – San Jose SJC