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$63+ 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 12/5. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Nov 25 — Dec 21
Tue 11/25
Tue 12/2
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 October 26, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$181
(Kiwi.com)

One-way from

$63
(Trip.com)

Popular in

December

Cheapest in

January

Average price

$298

Good round-trip deal

$296 or less

Good one-way deal

$165 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. 5% potential increase in price ($16 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
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Average for round-trip flights in October 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 October 26, 2025.

This Kiwi.com deal was found by Cheapflights users on 10/24. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/191:37 pmSEA - ORD
2 stops16h 09mFrontier
Thu 12/47:00 amORD - SEA
1 stop30h 53mFrontier
Deal found 10/24$181
This Kiwi.com deal was found by Cheapflights users on 10/24. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/241:01 pmSEA - ORD
2 stops16h 32mFrontier
Thu 11/276:45 pmORD - SEA
1 stop20h 37mFrontier
Deal found 10/24$182
This Kiwi.com deal was found by Cheapflights users on 10/25. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/812:58 pmSEA - ORD
1 stop8h 31mFrontier
Thu 11/132:42 pmORD - SEA
2 stops23h 31mFrontier
Deal found 10/25$183
This Expedia deal was found by Cheapflights users on 10/24. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/245:49 pmSEA - ORD
Nonstop4h 10mMultiple Airlines
Mon 12/87:00 amORD - SEA
1 stop6h 53mMultiple Airlines
Deal found 10/24$184
This Kiwi.com deal was found by Cheapflights users on 10/25. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/1312:58 pmSEA - ORD
1 stop9h 17mFrontier
Thu 11/276:45 pmORD - SEA
1 stop20h 37mFrontier
Deal found 10/25$185
This Kiwi.com deal was found by Cheapflights users on 10/24. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/1312:58 pmSEA - ORD
2 stops19h 43mFrontier
Sat 11/157:15 amORD - SEA
1 stop6h 58mFrontier
Deal found 10/24$186
This Alaska Airlines deal was found by Cheapflights users on 10/26. 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 12/1012:18 amSEA - ORD
Nonstop4h 03mAlaska Airlines
Wed 12/178:00 amORD - SEA
Nonstop4h 52mAlaska Airlines
Deal found 10/26$187
This Southwest deal was found by Cheapflights users on 10/25. 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 11/196:35 amSEA - MDW
Nonstop3h 55mSouthwest
Thu 11/205:15 amMDW - SEA
1 stop8h 40mSouthwest
Deal found 10/25$187
This Kiwi.com deal was found by Cheapflights users on 10/26. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/135:50 pmSEA - ORD
Nonstop4h 09mMultiple Airlines
Mon 12/157:00 amORD - SEA
1 stop6h 53mMultiple Airlines
Deal found 10/26$188
This Orbitz deal was found by Cheapflights users on 10/24. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/1312:58 pmSEA - ORD
1 stop9h 17mMultiple Airlines
Sun 11/168:00 amORD - SEA
Nonstop4h 44mMultiple Airlines
Deal found 10/24$189
This Kiwi.com deal was found by Cheapflights users on 10/24. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/139:08 amSEA - ORD
1 stop11h 52mFrontier
Mon 11/1710:43 pmORD - SEA
2 stops39h 24mFrontier
Deal found 10/24$190
This Kiwi.com deal was found by Cheapflights users on 10/24. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/65:21 pmSEA - MDW
2 stops22h 51mFrontier
Mon 12/86:15 amMDW - SEA
1 stop12h 21mFrontier
Deal found 10/24$190

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 October 26, 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 12/13

12:18 am-6:21 am

Nonstop4h 03m

Chicago O'Hare Intl

Mon 1/5

6:00 am-8:45 am

Nonstop4h 45m

$187

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Thu 12/11

12:18 am-6:21 am

Nonstop4h 03m

Chicago O'Hare Intl

Mon 1/5

8:00 am-10:47 am

Nonstop4h 47m

$187

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Mon 11/24

5:49 pm-11:59 pm

Nonstop4h 10m

Chicago O'Hare Intl

Fri 12/5

3:35 pm-6:22 pm

Nonstop4h 47m

$192

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Wed 11/19

9:35 am-5:10 pm

1 stop5h 35m

Chicago Midway

Thu 11/20

5:15 am-11:55 am

1 stop8h 40m

$196

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Wed 11/19

9:35 am-5:10 pm

1 stop5h 35m

Chicago Midway

Fri 11/21

5:25 pm-8:00 pm

Nonstop4h 35m

$197

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 1/10

9:25 am-10:35 pm

1 stop11h 10m

Chicago O'Hare Intl

Sun 1/11

4:25 pm-11:15 pm

1 stop8h 50m

$202

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Fri 12/5

4:21 pm-10:30 pm

Nonstop4h 09m

Chicago O'Hare Intl

Tue 12/9

3:05 pm-12:12 am

1 stop11h 07m

$207

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Thu 12/4

6:35 am-12:30 pm

Nonstop3h 55m

Chicago Midway

Wed 12/10

8:45 am-4:30 pm

1 stop9h 45m

$207

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Mon 12/8

10:43 am-4:55 pm

Nonstop4h 12m

Chicago O'Hare Intl

Tue 12/9

3:05 pm-12:12 am

1 stop11h 07m

$207

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Mon 12/8

6:35 am-12:30 pm

Nonstop3h 55m

Chicago Midway

Thu 12/11

8:45 am-4:30 pm

1 stop9h 45m

$217

Flights are sorted by cheapest round-trip flights first.

Deals found on 10/24

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, February is the cheapest month in which you can book a flight from Seattle to Illinois (average of $115). Flying from Seattle to Illinois in July is currently the most expensive (average of $169). 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 October 26, 2025.

It’s typically best to fly out from Seattle to Illinois in the afternoon. Doing so could potentially save you 20% on the flight price compared to flying in the morning, which is usually more expensive.

What is the cheapest day to fly from Seattle to Illinois?

Use this chart to determine the cheapest time to fly round-trip from Seattle to Illinois. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Seattle to Illinois flight should consider departing on Monday afternoons when fares are most often at their lowest. Monday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

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 October 26, 2025.

The most flights from SEA to USIL are scheduled on a Saturday (54 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (4 on average).

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 October 26, 2025.
Read through reviews of airlines operating flights from Seattle to Illinois, such as Alaska Airlines, Southwest, and Delta. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
11,191 reviews

Comfort

7.8

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

Food

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Alaska Airlines
8.0
Very good
11,191 reviews
Alaska Airlines
8.0
Very good
11,191 reviews

Comfort

7.8

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

Food

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Southwest
8.0
Very good
4,235 reviews
Alaska Airlines
8.0
Very good
11,191 reviews

Comfort

7.8

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

Food

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
Delta
7.9
Good
7,997 reviews
Alaska Airlines
8.0
Very good
11,191 reviews

Comfort

7.8

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

Food

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
United Airlines
7.4
Good
8,999 reviews
Alaska Airlines
8.0
Very good
11,191 reviews

Comfort

7.8

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

Food

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.
American Airlines
7.2
Good
11,030 reviews
Alaska Airlines
8.0
Very good
11,191 reviews

Comfort

7.8

Boarding

8.1

Overall

8.0

Entertainment

7.0

Crew

8.5

Food

7.1

Reviews

1 / 20
8.0
Excellent

Anonymous,Sep 2025

SEA - MKE

The crew were excellent, flight good, but the actual space for a person to occupy for 4 hours seems to get smaller and smaller 🤣. I am not overweight, and average height….very uncomfortable,, especially when I couldn’t recliner the seat at all, and the pocket in front doesn’t accommodate a water bottle.

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.

  • How long is the flight from Seattle to Illinois?

    Airlines like Alaska Airlines, Southwest, and Delta fly from Seattle to Illinois in about 4h 03m. The time it takes to get you to your destination can typically vary by up to 3h 24m. The distance between Seattle and Illinois is about 1715 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • 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 Southwest ($70), United Airlines ($74), and American Airlines ($170).

  • 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 Austrian Airlines (96%), Avianca (95%) or WestJet (92%) 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 $740 for a flight from Seattle to Illinois. The cheapest flight overall is $104 while the most popular route, (Seattle/Tacoma Intl - Chicago O'Hare Intl) is currently priced at $105.

  • 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, February is the cheapest month in which you can book a flight from Seattle to Illinois (average of $115). Flying from Seattle to Illinois in July is currently the most expensive (average of $169). 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.

See more FAQs

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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 October 26, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$107Average$196FlexibilityNo cancel feeOn-time65%
Hawaiian AirlinesCheapest$121Average$288FlexibilityNo cancel feeOn-time85%
DeltaCheapest$125Average$298FlexibilityNo cancel feeOn-timeN/A
FrontierCheapest$137Average$273FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$169Average$434FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$175Average$479FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$179Average$374FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$181Average$451FlexibilityNo cancel feeOn-time71%

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