Cab fares from Sea-Tac International Airport to downtown Seattle run $42-50 one-way, and are available through Yellow Cab.  Once downtown you can take your pick of cab companies. The best way to find one is to have the hotel or restaurant call one for you if none are waiting nearby.  During peak hours and weekends you may wait 10-15 minutes before getting one to stop or drive by.  While cabs are metered from the airport to downtown, cabs charge a flat fee (currently $40) from the downtown hotel zone to Sea-Tac Airport.  Sea-Tac Airport has an agreement with one taxi firm who's cabs are stationed in the Sea-Tac garage.  That firm is currently Yellow Cab.  STILA is the on site limo and town car provider at Sea-Tac established by the Port of Seattle. Since they charge fixed rates, the amount for a limo into Seattle is often as cheap as a cab.  Town cars and limos from the airport are available by calling #55 from the phone near the hotel ads in baggage claim. a The current rates are $45 for a town car and $29 for 'flat rate' for hire vehicles. 

Seattle has a new type of taxi service that offers a flat rate based on zip code.  This can save you a lot of money as it's not metered by time or mileage. You must pre-book these trips. They currently offer a rate from downtown to Sea-Tac for $29.  This works from the airport to downtown as well.  One of the largest of these firms is Flat Rate for Hire. They have 400 cars which cover the Seattle metro area.  You just call or text them when you need a cab.

There is a pretty nice fare estimating tool available which gives you the ability to compare taxi fares.  The site lets you plug in an origin and destination, then comes up with a fare which doesn't include any airport fees. In general the for hire vehicles almost always are cheaper than a metered cab. The advantages multiply if you arrive in rush hour or during heavy traffic. Wait time in cabs are charged at $.50 a minute, whereas for hire vehicles are always a flat rate.

New app-based "ride-share" services make hailing a ride to/from the airport easy from your smartphone. Uber (blackcar, SUV and UberX rideshare, Lyft and Sidecar are all services operating in Seattle with similar pricing to taxis and towncars services. 

The ''official' airport taxi fare estimator shows an average fare from Sea-Tac to downtown Seattle at $52.50 making the fixed rate STILA limos a great value.

Farwest Taxi

Flat Rate for Hire

Orange Cab

Yellow Cab 

Sea-Tac Airport Ground Transportation  

Taxi Fare Estimator