All rental car companies currently operating at SeaTac do so at an off-site rental car facility. A free shuttle bus leaving the Airport North and South baggage claims will take you to the facility 24-hour-a-day, 365 days a year, in only a few minutes!
Take one of the shuttle buses leaving from the Airport North and South baggage claims. The shuttle will drop you off on the 5th floor of the car rental facility. SIXT rental counter is conveniently located at the far right side of the floor.
You can easily return your rental car on Level 3 of SeaTac's Rental Car Facility, at 3150 South 160th Street, Seatac WA 98188.