Act fast to get a free companion pass on Southwest Airlines.

Southwest Airlines is offering its Companion Pass promotion again, allowing Rapid Rewards members to bring a friend for free on an unlimited number of flights between August 15 and September 30. To qualify, members must register for the promotion and purchase a flight before May 24. The promotion cannot be applied to flights booked before registration, and taxes and fees are not included. Members can change their designated flying buddy up to three times during the promotional pass period.