Singapore Airlines has select roundtrip flights to Asia on sale for as low as $680.26, as seen on Travelzoo. That's $17 under our mention from two weeks ago and the second-lowest price we've seen for fares from Singapore Airlines. It's also a current low for select routes by $675. This price is valid on flights departing from San Francisco, CA, (SFO) with arrival in Seoul, South Korea, (ICN) on March 12 and return on March 19; prices vary depending on the departure cities and dates chosen. Book this travel deal by March 31 for travel through May 31. Click here to see more routes.