SEA

$104 Find Cheap Flights from Illinois to Seattle - Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight to Seattle departing on 11/14. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Flight Deals

Cheap Flights from Illinois to Seattle

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Illinois to Seattle that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Illinois to Seattle

Wed, Sep 16 - Tue, Sep 22
United Airlines Logo
3:35 pm - 10:45 pmPIA  Greater Peoria-SEA Seattle/Tacoma Intl
9h 10m1 stop Chicago O'Hare Intl
United Airlines Logo
1:57 pm - 11:13 pmSEA  Seattle/Tacoma Intl-PIA Greater Peoria
7h 16m1 stop Chicago O'Hare Intl
$281United Airlines
Wed, Oct 7 - Wed, Oct 14
United Airlines Logo
4:05 pm - 10:56 pmPIA  Greater Peoria-SEA Seattle/Tacoma Intl
8h 51m1 stop Chicago O'Hare Intl
United Airlines Logo
1:56 pm - 10:58 pmSEA  Seattle/Tacoma Intl-PIA Greater Peoria
7h 02m1 stop Chicago O'Hare Intl
$281United Airlines
Wed, Sep 16 - Tue, Sep 22
American Airlines Logo
5:28 pm - 12:11 amPIA  Greater Peoria-SEA Seattle/Tacoma Intl
8h 43m1 stop Chicago O'Hare Intl
American Airlines Logo
3:41 pm - 12:08 amSEA  Seattle/Tacoma Intl-PIA Greater Peoria
6h 27m1 stop Chicago O'Hare Intl
$281American Airlines
Tue, Sep 22 - Tue, Sep 29
American Airlines Logo
5:28 pm - 12:11 amPIA  Greater Peoria-SEA Seattle/Tacoma Intl
8h 43m1 stop Chicago O'Hare Intl
American Airlines Logo
3:41 pm - 12:08 amSEA  Seattle/Tacoma Intl-PIA Greater Peoria
6h 27m1 stop Chicago O'Hare Intl
$281American Airlines
Tue, Sep 22 - Tue, Sep 29
Frontier Logo
6:30 am - 3:08 pmORD  Chicago O'Hare Intl-SEA Seattle/Tacoma Intl
10h 38m1 stop Denver Intl
Frontier Logo
4:27 pm - 2:17 pmSEA  Seattle/Tacoma Intl-ORD Chicago O'Hare Intl
19h 50m2 stops Denver Intl Houston George Bush Intcntl
$282Frontier
Mon, Sep 7 - Mon, Sep 14
Frontier Logo
8:11 pm - 10:39 amORD  Chicago O'Hare Intl-SEA Seattle/Tacoma Intl
16h 28m1 stop Las Vegas Harry Reid Intl
Frontier Logo
7:45 pm - 5:38 amSEA  Seattle/Tacoma Intl-ORD Chicago O'Hare Intl
7h 53m1 stop Las Vegas Harry Reid Intl
$282Frontier
Mon, Nov 2 - Tue, Nov 3
Southwest Logo
10:00 am - 7:15 pmMDW  Chicago Midway-SEA Seattle/Tacoma Intl
11h 15m2 stops Indianapolis Austin Bergstrom
Southwest Logo
8:15 pm - 5:55 amSEA  Seattle/Tacoma Intl-MDW Chicago Midway
7h 40m1 stop Oakland
$283Southwest
Tue, Sep 15 - Thu, Sep 17
Southwest Logo
4:45 pm - 11:30 pmMDW  Chicago Midway-SEA Seattle/Tacoma Intl
8h 45m1 stop Las Vegas Harry Reid Intl
Southwest Logo
12:35 pm - 11:25 pmSEA  Seattle/Tacoma Intl-MDW Chicago Midway
8h 50m2 stops Austin Bergstrom Dallas Love Field
$283Southwest
Sat, Dec 5 - Sat, Dec 5
Alaska Airlines Logo
2:54 pm - 10:07 pmORD  Chicago O'Hare Intl-SEA Seattle/Tacoma Intl
9h 13m1 stop San Diego
Alaska Airlines Logo
12:58 am - 7:00 amSEA  Seattle/Tacoma Intl-ORD Chicago O'Hare Intl
4h 02mnonstop
$292Alaska Airlines
Mon, Nov 2 - Tue, Nov 3
Alaska Airlines Logo
7:56 pm - 2:47 pmORD  Chicago O'Hare Intl-SEA Seattle/Tacoma Intl
20h 51m1 stop San Diego
Alaska Airlines Logo
5:46 pm - 11:57 pmSEA  Seattle/Tacoma Intl-ORD Chicago O'Hare Intl
4h 11mnonstop
$298Alaska Airlines
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Good to know

Low season

January

Cheapest flight

$104
Best time to beat the crowds with an average 23% drop in price.
Most popular time to fly with an average 25% increase in price.
Flight from St. Louis to Seattle

Flights from Illinois to Seattle: the best tips from KAYAK users

Insights shared by verified travelers who flew the route from Illinois to Seattle 
Learn how KAYAK collects reviews and tips from users.
MatthewFlew with United Airlines-Jul 2026
When in Seattle, take public trans at least to downtown as Uber/Lyft is expensive
PaulFlew with Alaska Airlines-Apr 2024
The flight is long, at over four hours. I would try to get a window or aisle seat to be more comfortable. I would check with other airlines that allow you to choose your seat even if you are in the economy section. I would bring your own food on the plane as the service was sometimes sketchy.
Verified travelerFlew with Alaska Airlines-Apr 2024
If you miss your flight ask any alaska agent to how and where to rebook the flight.

FAQs for booking flights from Illinois to Seattle

  • How does KAYAK find such low prices on flights from Illinois to Seattle?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Illinois to Seattle.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Illinois to Seattle?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Seattle from Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Illinois to Seattle?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Seattle with an airline and back to Illinois with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Illinois to Seattle?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Seattle from Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Everything you need to know for your flight to Seattle

Information on the airport you'll fly into in Seattle

Seattle (SEA)