DALLAS (AP) -- If you're looking to cash in points to earn a free flight on Southwest Airlines Co., it could take you a little longer.
Southwest is telling customers that if they use points to redeem its cheapest fares, called Wanna Get Away, they'll need 70 points for every $1 in fare. That's up from 60 points per $1 now. For example, if the base fare plus excise tax for a round-trip Wanna Get Away ticket is $200, a reward trip currently costs 12,000 points. That will rise to 14,000 points.
Southwest isn't changing how passengers earn points. Passengers earn six points for every dollar spent on Wanna Get Away fares. So customers who always buy the cheapest seat will need to spend $333 more with Southwest to earn the extra 2,000 points for that same $200 ticket.
The change will take effect on bookings made next March 31. The company isn't raising the points needed to redeem a flight at higher Anytime and Business Select fares.
In an email to customers, Southwest marketing official Ryan Green said the airline will continue to make all seats available for reward redemption without blackout dates and without points expiring. "We hope you understand that in order to continue providing these benefits, we must make changes to the Rapid Rewards Program from time to time," he wrote.
Some passengers went on Twitter and frequent-flier websites to complain.
The original Rapid Rewards program was simple: Customers who paid for eight round-trip tickets within two years earned a free trip. In 2011, Southwest changed to a more complicated point system that rewards customers who buy higher-priced tickets. That has been an advantage for business travelers, who typically spend more than vacationers.
Southwest shares rose 2 cents to close at $14.43. They have jumped 41 percent so far in 2013.