Singapore Airlines has select roundtrip international flights on sale for as low as $857.58, as provided by ShermansTravel. (Click on "" in the main paragraph to see this sale; all taxes are included.) That's the lowest current rate we could find for select routes by $22. This price is valid on flights departing from San Francisco, CA, (SFO) to Seoul, South Korea, (ICN) on May 14; prices vary depending on the departure cities and dates chosen. Available destinations include Tokyo, Seoul, Hong Kong, and more. Blackout dates may apply. Book this travel deal by May 5 for travel through June 9. Other notable fares: