The Southwest Companion Pass is eligible for unlimited flights – both domestic and international. And while Southwest doesn't have a huge international route network, you can use it to fly you and your companion all over the U.S., Mexico, the Carribean, and even the airline's flights to (and within) Hawaii.

Yes, you can absolutely use the Southwest Companion Pass for international flights, including destinations in Mexico (such as Cancun, Cabo San Lucas, and Puerto Vallarta). The Companion Pass allows you to bring one designated person with you on any Southwest flight you book, whether you paid for your ticket with cash or Rapid Rewards points. The only cost for the companion on an international flight is the government-imposed taxes and fees, which for Mexico typically range from $90 to $120 USD roundtrip. This is significantly higher than the standard $5.60 domestic security fee, so you should be prepared for that extra cost at checkout. In 2026, this remains one of the single best values in travel, as it effectively gives you a "Buy One, Get One Free" deal on international tropical vacations. You must book your own flight first and then add your companion through the "My Account" section of the Southwest website or app, ensuring there is at least one seat still available for sale on the aircraft at the time of the companion booking.