I have a five hour layover at SEA, and I've never actually been to Seattle proper so I was curious if that was enough time to get out to the city for a late lunch. I figured I really only have four hours if I do this because I'll need to check back in, so is four hours enough to get to and from the airport and Seattle, and get something to eat and do a little sightseeing?
I agree with Debbie, you will have to hurry a bit, but its do-able! Taking the light rail including walking time will take about 45 minutes each way, so you'll have 2.5 hours of restaurant time and sightseeing.
Restaurants tend to be pretty efficient downtown so you'll probably be able to be in and out in an hour and a half. My favorite restaurants near Pike Place Market are:
In your remaining hour of sightseeing you could:
Seattle is great! Definately worth the treck into town to check out a few things. Have fun!
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Four free hours is cutting it a tad close, but if you don't mind making haste, then yes! Lucky for you, SEA is very close to Downtown Seattle (I'm assuming that's the part of Seattle you'd like to visit!) and it's very convenient to take a cab or the train there. Without traffic, a cab takes about 20 minutes and last I checked in 2012, it cost a flat rate of $40. Like I mentioned, there's also a train that you can take from the airport to downtown, which is a lot more affordable. The Link Light Rail costs less than $2 (last I checked in 2012, it was $1.75), but takes slightly longer, about 40 minutes. Here's more info on how to get from the airport to downtown: http://www.trippy.com/question/Best-way-to-get-to-Downtown-Seattle-from-SEA
If you don't have any particular place in mind to check out, I would suggest the very famous Pike Place Market. There's a Link Light Rail station just four blocks away -- the Westlake Station. You can browse the market, see the water, the flying fish market, eat at a seafood restaurant, visit the gum wall, drink some coffee (the very first ever Starbucks is there), pick up some souvenirs, and just take in the sights and sounds. Should you have time, the area around the market is nice to peruse around, too.