With Southwest Airlines' latest promotion, you can go to Hawaii and get future flights for yourself and a plus-one for free.

Travelers who register for the promotion and book a round-trip ticket or two one-way tickets to Hawaii by Friday, with travel happening between June 1 and July 31, will qualify for a companion pass to use between Oct. 5 and Nov. 15. To qualify, travelers must be enrolled in the Rapid Rewards frequent flyer program.

Southwest is running the promo to recognize five years of serving five airports in Hawaii.

"This is a great opportunity to HI 5 our Customers for supporting five years of Southwest service in five airports across Hawaii by showcasing and sharing one of the great perks of being part of our Rapid Rewards program," Jonathan Clarkson, Vice President of Marketing at Southwest Airlines said in a statement. "Hawaii on Southwest is available nonstop from eight mainland gateways, and we're excited for this opportunity to truly connect our Customers for travel between the mainland and the Hawaiian islands."

A companion pass allows the holder to designate another traveler to fly with them for free on all Southwest flights they purchase during the validity period of the pass. It’s a coveted perk of elite Rapid Rewards status and there are worse ways to earn one than a vacation to the tropics.