Singapore Airlines has released a spring sale for flights to Seoul, South Korea, from San Francisco. Fly nonstop on the top-rated airline for just $681 roundtrip -- including all taxes and fees.

This sale price saves hundreds off the cost of one-stop flights on other airlines, while offering the unmatched service of Singapore Airlines. This fare is for departures through May 13 and returns through May 31. Book by March 22.

Singapore Airlines was named World's Best International Airline by Conde Nast Traveler magazine, World's Best International Airline by Travel + Leisure magazine and Best Overall Airline in the World by Global Traveler magazine.

To book with Singapore Airlines, click here. Check "Search by price +/- 3 days" to find the lowest fare.