I think it's quite convenient compared to some other places I've been.
Get there early. Also i have a hard time finally getting my deposits back on the cars i rent.
I thought the rental car facility was convenient being that all the car rental places are in one building and they have one shuttle (more than one shuttle of course) that picks up everyone no matter who you rent a car from. I've been to places where there's a separate shuttle for each car rental place and located in different areas so I found Seatac rental facility very convenient. The downside is trying to find your rental car once you get it. The signs were kind of confusing but someone was there to help outside. There's a worker for each rental place outside on each floor. I didn't have a problem with traffic. It was actually dead though I arrived at 9pm during the week and then departed on a Monday at 10am. Getting to Seatac airport was very heavy traffic however, we drove in the carpool lane so it was smooth sailing. I will say Im not a fan of Seatac airport because the signs didn't help us where to go and thats if I even came across a sign.
Traffic is bad regardless, with regards to the rental car facility I recommend the elevator over the escalators.
If your there during rush hour its bad
I had a great experience. Maybe different opinion upon return & making flight...won't know until the 24th.
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