Frontier Miles: 20,000 Bonus Miles for Former Spirit Customers — Register by May 31

Spirit’s collapse left a lot of travelers with plans but no planes. Frontier is moving fast to scoop up that stranded loyalty. The offer is a "Fly One, Get One" bonus: 5,000 extra miles per eligible round trip, up to four trips, through August 31. Domestic Value awards start at 5,000 miles one-way, so 20,000 bonus miles can cover four separate flights when Value-tier inventory is open. The catch: register at flyfrontier.com before May 31 at 11:59 PM MT and at least 24 hours before your first departure. Bonus miles post within three business days after each round trip completes.

What qualifies:

• Registration: Required at flyfrontier.com/earn-up-to-20K-miles — closes May 31, 2026, at 11:59 PM MT (must also register at least 24 hours before departure)
• Booking window: Purchases made directly at Flyfrontier.com on or after May 6, 2026
• Travel window: Round trips completed by August 31, 2026, at 11:59 PM MT
• Bonus structure: 5,000 miles per eligible round trip, up to 4 round trips (20,000 miles maximum)
• Eligible booking: Flyfrontier.com direct purchases only
• Excluded: GoWild fares, award tickets, group bookings, charter flights, and free tickets
• Bonus posting: Within 3 business days after each qualifying round trip completes
• Discount Den enrollment: Enrollment fee ($50) waived through May 15, 2026 at 11:59 PM MT — annual membership is $59.99; limited to one waiver per member/email
• Referral bonus: Earn a $25 Frontier voucher per referral (Discount Den signups using your Frontier Miles number as code), up to 10 referrals ($250 maximum); vouchers delivered within 30 days; offer ends May 15, 2026

The Discount Den waiver is a time-sensitive side deal: you're paying $59.99 for year-round access to Frontier's lowest fares instead of $109.99. If you fly Frontier even two or three times a year, that math works. One caveat on the miles: the "four one-way domestic flights" framing holds only when Value-tier inventory is available — it sells out fast on peak weekends and holidays. Book early, fly mid-week or off-peak, and that 5K floor holds up. Try to use 20,000 miles on a Thanksgiving Friday and you may be staring at Standard or Last Seat pricing. Love this for displaced Spirit flyers looking for a new home base. Less compelling if you're just speculating on a miles balance.