Southwest Airlines is offering a special discount code for Rapid Rewards members who redeem points for their next flight.

The sale, which ends today, August 19, at 11:59 p.m. PT, offers up to 25 percent off travel between September 4 and December 10, according to the airline. Travelers need to enter promo code “SAVE25NOW” when looking up flights on Southwest’s website.  

However, the promo code won’t apply to all Southwest flights, as inter-island Hawaii and Orange County flights are specifically excluded from this sale. In addition, there are several blackout dates for this offer: 

• Continental U.S. flights are valid any day of the week but excluded from Oct. 14, Nov. 22 to 27, and Nov. 29 to Dec. 2
• Flights to Hawaii, Puerto Rico, and international destinations are valid Sundays through Wednesdays, excluded from Nov. 21 to 25
• Flights from Hawaii, Puerto Rico, and international destinations are valid Tuesdays through Fridays, excluded from Nov. 29 to Dec. 3

If the discount code is successfully applied, a green banner will appear on the screen that reads, “Score! Promo code SAVE25NOW has been applied. Enjoy your extra savings below!” Furthermore, all one-way domestic ticket redemptions will include $5.60 in taxes and fees, while round-trip tickets will have $11.20 in taxes and fees.

Travel + Leisure found many routes eligible for this sale:  

• Nashville (BNA) to/from New York (LGA): 3,178 points (discounted from 4,238 points) 
• Fort Lauderdale (FLL) to/from San Juan (SJU): 3,735 points (discounted from 4,669 points)
• Atlanta (ATL) to/from Philadelphia (PHL): 5,010 points (discounted from 6,263 points)
• Denver (DEN) to/from Chicago (MDW): 4,336 points (discounted from 4,336 points)
• Phoenix (PHX) to/from Honolulu (HNL): 16,340 points (discounted from 21,786 points)

Southwest’s new Point + Cash redemption option isn’t eligible for the sale, so travelers will want to make sure they’ve got plenty of Rapid Rewards points ready before checkout. The airline is also selling Rapid Rewards points for up to 50 percent off by tonight, bringing down the cost of each point to 1.5 cents apiece.