The three-day cheap fare bonanza features the $49 one-way fares from a whole bunch of departure cities, though there are some seriously enticing deals to be had from almost every airport Southwest serves. The only catch is you need to book by 11:59pm on March 15.
Among the standout domestic deals currently up for grabs are $49 flights from San Francisco to Las Vegas (and vice versa), $49 flights from Nashville to Atlanta, $64 flights from Los Angeles to Las Vegas (and vice versa), $79 flights from Chicago to Newark, and Portland to San Francisco for $54.
As for international options, there are $59 flights from Ft. Lauderdale to Turks & Caicos, $59 flights from Ft. Lauderdale to the Cayman Islands, and $99 flights from Tampa to Cuba. You can peep all the deals (and sort by destination city) on Southwest's flash sale site.