The Dallas-based carrier said revenues grew 5.6 percent to $4.8 billion in the quarter even though the average passenger fare increased less than a percent to $160.74.
"Revenue momentum has continued into October 2014, with favorable load factors and unit revenue trends," said Southwest chief executive Gary Kelly in a statement. "Current bookings for November and December are also good."
Excluding one-time accounting items, Southwest said income was $382 million, or 55 cents per share, beating Wall Street analysts' expectations of 53 cents per share, according to FactSet Research.
Shares of Southwest are up 82 percent since the beginning of the year, trading around $34 a share.
Jet fuel prices continued to decline as Southwest said it paid $2.94 per gallon, down from $3.06 per gallon in the third quarter of 2013.
The company also paid out about $100 million in profit sharing to its employees in the quarter. On Wednesday, Southwest reached a tentative contract agreement with its passenger service agents that included pay raises and signing bonuses.