Finding cheap flights from San Francisco International Airport (SFO) to London Heathrow Airport (LHR) in October requires a combination of timing, flexibility, and tool usage. Primary strategies include booking 6–10 weeks in advance, traveling mid-week (Tuesday–Thursday), and flying red-eye nonstop or one-stop itineraries with efficient connections. Secondary tactics include using fare comparison sites (Google Flights, Skyscanner), setting price alerts, and checking airline sale pages for United, British Airways, and Virgin Atlantic. Consider alternative nearby airports on the departure or return (e.g., Oakland or San Jose for outbound alternatives, though LHR is the primary London hub) and be open to off-peak return dates to secure lower round-trip fares.