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$85+ Cheap flights from Seattle (SEA) to Illinois

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 5/24. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Apr 2 — Apr 91
Wed 4/2
Wed 4/9
1 adult, Economy
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Cheap flight deals from Seattle to Illinois

Keep the following information in mind while searching for Seattle to Illinois flight deals. Data was last updated March 28, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$168
(Trip.com)

One-way from

$85
(Alaska Airlines)

Popular in

December

Cheapest in

January

Average price

$323

Good round-trip deal

$299 or less

Good one-way deal

$170 or less
Provider with most accurate pricing for Seattle/Tacoma Intl-Chicago (CHI) flight deals.
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Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Chicago (CHI) flights.
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From Seattle/Tacoma Intl to Illinois
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One-way flight from Seattle/Tacoma Intl to Illinois
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Highest demand for flights based on searches. 2% potential increase in price ($7 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($8 potential savings vs. average RT price).
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Average for round-trip flights in March 2025
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Price to beat on a round-trip flight from Seattle/Tacoma Intl to Illinois.
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Price to beat on a one-way flight from Seattle/Tacoma Intl to Illinois.
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Find flight deals from Seattle to Illinois

Cheapest flights from Seattle to Illinois
Explore the most affordable flight options available from Seattle to Illinois. Find the lowest fares from popular airlines and budget airlines, with prices last updated on March 28, 2025.

This Trip.com deal was found by Cheapflights users on 3/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/197:55 amSEA - ORD
Nonstop4h 21mMultiple Airlines
Sat 4/266:00 amORD - SEA
Nonstop4h 30mMultiple Airlines
Deal found 3/26$168
This Delta deal was found by Cheapflights users on 3/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/235:55 pmSEA - ORD
Nonstop4h 04mDelta
Wed 4/307:50 amORD - SEA
Nonstop4h 40mDelta
Deal found 3/26$169
This American Airlines deal was found by Cheapflights users on 3/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/191:35 pmSEA - ORD
Nonstop4h 05mAmerican Airlines
Sat 4/267:35 amORD - SEA
Nonstop4h 40mAmerican Airlines
Deal found 3/26$170
This Mytrip deal was found by Cheapflights users on 3/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/2312:30 pmSEA - ORD
2 stops15h 15mSpirit Airlines
Tue 4/295:36 amORD - SEA
2 stops31h 59mSpirit Airlines
Deal found 3/27$172
This Hawaiian Airlines deal was found by Cheapflights users on 3/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/2011:36 pmSEA - ORD
Nonstop4h 04mHawaiian Airlines
Tue 4/225:56 pmORD - SEA
Nonstop4h 36mHawaiian Airlines
Deal found 3/26$174
This United Airlines deal was found by Cheapflights users on 3/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/222:18 pmSEA - ORD
Nonstop4h 07mUnited Airlines
Wed 4/237:00 amORD - SEA
1 stop8h 59mUnited Airlines
Deal found 3/27$175
This Alaska Airlines deal was found by Cheapflights users on 3/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/284:19 pmSEA - ORD
Nonstop4h 04mAlaska Airlines
Sat 5/317:59 pmORD - SEA
1 stop15h 10mAlaska Airlines
Deal found 3/26$184
This Southwest deal was found by Cheapflights users on 3/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/236:00 amSEA - MDW
Nonstop4h 10mSouthwest
Tue 4/292:20 pmMDW - SEA
1 stop11h 30mSouthwest
Deal found 3/27$184
This Southwest deal was found by Cheapflights users on 3/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/232:50 pmSEA - ORD
1 stop6h 15mSouthwest
Wed 4/302:50 pmORD - SEA
1 stop11h 00mSouthwest
Deal found 3/26$194
This Delta deal was found by Cheapflights users on 3/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/311:50 pmSEA - STL
1 stop8h 57mDelta
Fri 6/66:14 pmSTL - SEA
1 stop7h 33mDelta
Deal found 3/27$229
This Southwest deal was found by Cheapflights users on 3/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 5/25:35 amSEA - STL
1 stop5h 35mSouthwest
Sun 5/46:45 pmSTL - SEA
1 stop8h 30mSouthwest
Deal found 3/27$233
This Hawaiian Airlines deal was found by Cheapflights users on 3/27. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 5/38:03 amSEA - STL
Nonstop4h 05mHawaiian Airlines
Tue 5/66:30 amSTL - SEA
Nonstop4h 24mHawaiian Airlines
Deal found 3/27$237

Cheapflights Fare Finder

Customize your flight search to find flights from Seattle to Illinois that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 28, 2025.
Use the filters below to find and compare flights from Seattle to Illinois that are best for you.

Fly from

Seattle

Fly to

Illinois

Route

Depart

Return

Price

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 4/19

7:55 am-2:16 pm

Nonstop4h 21m

Chicago O'Hare Intl

Sat 4/26

6:00 am-8:30 am

Nonstop4h 30m

$168

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Wed 4/23

11:48 am-6:01 pm

Nonstop4h 13m

Chicago O'Hare Intl

Sat 4/26

6:00 am-8:30 am

Nonstop4h 30m

$169

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 4/19

1:35 pm-7:40 pm

Nonstop4h 05m

Chicago O'Hare Intl

Sat 4/26

7:35 am-10:15 am

Nonstop4h 40m

$170

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Wed 4/23

12:30 pm-5:45 am

2 stops15h 15m

Chicago O'Hare Intl

Tue 4/29

5:36 am-11:35 am

2 stops31h 59m

$172

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Tue 4/22

2:18 pm-8:25 pm

Nonstop4h 07m

Chicago O'Hare Intl

Wed 4/23

7:00 am-1:59 pm

1 stop8h 59m

$175

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Wed 5/28

4:19 pm-10:23 pm

Nonstop4h 04m

Chicago O'Hare Intl

Sat 5/31

7:59 pm-9:09 am

1 stop15h 10m

$184

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Wed 4/23

6:00 am-12:10 pm

Nonstop4h 10m

Chicago Midway

Tue 4/29

2:20 pm-11:50 pm

1 stop11h 30m

$184

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Wed 4/23

2:50 pm-11:05 pm

1 stop6h 15m

Chicago O'Hare Intl

Wed 4/30

2:50 pm-11:50 pm

1 stop11h 00m

$194

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Thu 5/1

5:55 pm-11:59 pm

Nonstop4h 04m

Chicago O'Hare Intl

Tue 5/6

6:25 pm-9:12 pm

Nonstop4h 47m

$199

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Tue 6/3

11:50 pm-10:47 am

1 stop8h 57m

Lambert-St Louis

Fri 6/6

6:14 pm-11:47 pm

1 stop7h 33m

$229

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/26

Showing 1-10 of 60 results
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Best time to book a flight from Seattle to Illinois

Have a flexible travel schedule? Discover the best time to fly to Illinois from Seattle with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

Everything you need to know about your flight from Seattle to Illinois

What is the cheapest month to book a flight from Seattle to Illinois?

Currently, August is the cheapest month in which you can book a flight from Seattle to Illinois (average of $245). Flying from Seattle to Illinois in March is currently the most expensive (average of $323). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from SEA to IL?

Find hourly flight availability from Seattle to Illinois. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated March 28, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to Illinois as you normally would.

Weekly flight availability from Seattle to Illinois

Explore weekly flight availability from Seattle to Illinois. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated March 28, 2025.

The most flights from SEA to USIL are scheduled on a Friday (44 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (17 on average).

Rainfall in Illinois by month

Plan your trip to Illinois by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Illinois ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Illinois when rainfall is around 1.7 in.

Temperature in Illinois by month

Plan your trip to Illinois by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Illinois, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).

Reviews of airlines servicing Illinois

Get insights into the airlines that provide service to Illinois. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Illinois. Reviews last updated March 28, 2025.
Read reviews from past customers who have flown Southwest, Alaska Airlines and Delta from Seattle to Illinois. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Overall

8.1

Comfort

8.1

Food

7.1

Boarding

8.2

Crew

8.7

Reviews

1 / 20
8.0
Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.
Southwest
8.1
Very good
4,274 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Overall

8.1

Comfort

8.1

Food

7.1

Boarding

8.2

Crew

8.7

Reviews

1 / 20
8.0
Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.
Alaska Airlines
8.0
Very good
9,798 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Overall

8.1

Comfort

8.1

Food

7.1

Boarding

8.2

Crew

8.7

Reviews

1 / 20
8.0
Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.
Delta
8.0
Very good
7,897 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Overall

8.1

Comfort

8.1

Food

7.1

Boarding

8.2

Crew

8.7

Reviews

1 / 20
8.0
Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.
Hawaiian Airlines
7.9
Good
2,336 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Overall

8.1

Comfort

8.1

Food

7.1

Boarding

8.2

Crew

8.7

Reviews

1 / 20
8.0
Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.
United Airlines
7.4
Good
8,603 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Overall

8.1

Comfort

8.1

Food

7.1

Boarding

8.2

Crew

8.7

Reviews

1 / 20
8.0
Excellent

Ila,Mar 2025

HOU - DAL

Our original flight was delayed. We were able to change our flight and got home at close to the same time. Looking forward to when you have assigned seating.

Related info for your journey

Find useful and relevant information for your journey from Seattle to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Seattle to Illinois?

    Most people fly from Seattle/Tacoma Intl (SEA) if they book a flight from Seattle to Illinois. Seattle/Tacoma Intl is conveniently located just 11.4 mi from Seattle’s city center.

  • What are the cheapest airlines to fly from Seattle to Illinois one-way?

    The cheapest airlines for a one-way flight from Seattle to Illinois are Alaska Airlines ($85), Southwest ($85), and Spirit Airlines ($88).

  • What are the most popular routes from Seattle to Illinois?

    The most popular flight routes from Seattle to Illinois are Seattle/Tacoma Intl - Chicago O'Hare Intl, Seattle/Tacoma Intl - Chicago Midway and Seattle/Tacoma Intl - Lambert-St Louis.

  • What are the most reliable airlines from Seattle to Illinois?

    No one likes to see their flight delayed. When booking a flight from Seattle to Illinois consider choosing United Airlines (91%), Avianca (91%) or American Airlines (89%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Seattle to Illinois?

    On average you can expect to pay $973 for a flight from Seattle to Illinois. The cheapest flight overall is $105 while the most popular route, (Seattle/Tacoma Intl - Chicago O'Hare Intl) is currently priced at $162.

  • Can I find deals for flights from Seattle to Illinois that include hotel bookings?

    Yes. In addition to deals on Seattle to Illinois flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Seattle to Illinois?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Seattle to Illinois.

  • Can I find deals for business class flights from Seattle to Illinois?

    Yes. Cheapflights offers flight deals from Seattle to Illinois by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Seattle to Illinois?

    Currently, August is the cheapest month in which you can book a flight from Seattle to Illinois (average of $245). Flying from Seattle to Illinois in March is currently the most expensive (average of $323). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

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Alternative routes for Seattle to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
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Top 8 airlines flying from Seattle to Illinois

Discover the top 8 airlines that operate flights from Seattle to Illinois. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$107Average$235FlexibilityNo cancel feeOn-time65%
DeltaCheapest$107Average$445FlexibilityNo cancel feeOn-timeN/A
Hawaiian AirlinesCheapest$119Average$278FlexibilityNo cancel feeOn-time85%
FrontierCheapest$138Average$243FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$156Average$480FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$156Average$503FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$160Average$534FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$200Average$400FlexibilityNo cancel feeOn-time63%
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