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$87+ 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 7/22. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Jul 7 — Jul 141
Mon 7/7
Mon 7/14
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 July 2, 2025.

Round-trip from

$165
(SmartFares)

One-way from

$87
(KAYAK)

Popular in

December

Cheapest in

January

Average price

$326

Good round-trip deal

$297 or less

Good one-way deal

$162 or less
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. 4% potential increase in price ($13 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 July 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 July 2, 2025.

This SmartFares deal was found by Cheapflights users on 7/1. 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 SmartFares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/2212:59 amSEA - ORD
Nonstop4h 04mHawaiian Airlines
Sun 8/3110:00 amORD - SEA
Nonstop4h 34mHawaiian Airlines
Deal found 7/1$165
This Priceline deal was found by Cheapflights users on 6/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/266:12 amSEA - MDW
1 stop7h 41mFrontier
Mon 9/294:48 pmMDW - SEA
1 stop9h 42mFrontier
Deal found 6/30$167
This Cheapflightsfares deal was found by Cheapflights users on 7/1. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/215:30 pmSEA - ORD
1 stop10h 33mSpirit Airlines
Tue 7/227:08 amORD - SEA
1 stop11h 17mSpirit Airlines
Deal found 7/1$168
This Priceline deal was found by Cheapflights users on 6/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/1812:13 pmSEA - ORD
1 stop8h 42mFrontier
Sat 8/237:00 amORD - SEA
1 stop6h 45mFrontier
Deal found 6/30$169
This Priceline deal was found by Cheapflights users on 6/30. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/2512:13 pmSEA - ORD
1 stop8h 42mMultiple Airlines
Tue 7/297:08 amORD - SEA
1 stop11h 17mMultiple Airlines
Deal found 6/30$172
This Netflights deal was found by Cheapflights users on 6/30. 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 Netflights is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/2212:59 amSEA - ORD
Nonstop4h 04mAlaska Airlines
Sun 8/318:00 amORD - SEA
Nonstop4h 34mAlaska Airlines
Deal found 6/30$182
This Delta deal was found by Cheapflights users on 6/30. 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.
Sat 8/235:50 pmSEA - ORD
Nonstop4h 01mDelta
Sun 8/317:15 amORD - SEA
Nonstop4h 30mDelta
Deal found 6/30$184
This Southwest deal was found by Cheapflights users on 6/30. 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.
Sat 8/2311:10 pmSEA - MDW
Nonstop4h 05mSouthwest
Sun 8/318:20 pmMDW - SEA
Nonstop4h 30mSouthwest
Deal found 6/30$184
This Southwest deal was found by Cheapflights users on 6/30. 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.
Sat 8/238:10 amSEA - ORD
1 stop7h 45mSouthwest
Sun 8/317:30 amORD - SEA
1 stop9h 20mSouthwest
Deal found 6/30$203
This United Airlines deal was found by Cheapflights users on 6/30. 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 7/225:26 pmSEA - ORD
Nonstop4h 07mUnited Airlines
Sat 7/269:16 pmORD - SEA
Nonstop4h 43mUnited Airlines
Deal found 6/30$213
This American Airlines deal was found by Cheapflights users on 7/2. 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.
Fri 8/1512:46 amSEA - ORD
Nonstop4h 06mAmerican Airlines
Sat 8/236:50 amORD - SEA
Nonstop4h 29mAmerican Airlines
Deal found 7/2$221
This Orbitz deal was found by Cheapflights users on 7/2. 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 8/216:03 pmSEA - STL
Nonstop3h 56mMultiple Airlines
Sun 8/247:54 pmSTL - SEA
1 stop6h 40mMultiple Airlines
Deal found 7/2$242

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 July 2, 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

Fri 8/22

12:59 am-7:03 am

Nonstop4h 04m

Chicago O'Hare Intl

Sun 8/31

10:00 am-12:34 pm

Nonstop4h 34m

$165

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Fri 9/26

6:12 am-3:53 pm

1 stop7h 41m

Chicago Midway

Mon 9/29

4:48 pm-12:30 am

1 stop9h 42m

$167

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Mon 7/21

5:30 pm-6:03 am

1 stop10h 33m

Chicago O'Hare Intl

Tue 7/22

7:08 am-4:25 pm

1 stop11h 17m

$168

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Mon 8/18

12:13 pm-10:55 pm

1 stop8h 42m

Chicago O'Hare Intl

Sat 8/23

7:00 am-11:45 am

1 stop6h 45m

$169

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Fri 7/25

12:13 pm-10:55 pm

1 stop8h 42m

Chicago O'Hare Intl

Tue 7/29

7:08 am-4:25 pm

1 stop11h 17m

$172

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 8/23

5:55 pm-11:59 pm

Nonstop4h 04m

Chicago O'Hare Intl

Sat 8/30

2:07 pm-6:45 pm

1 stop6h 38m

$178

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 8/23

5:50 pm-11:51 pm

Nonstop4h 01m

Chicago O'Hare Intl

Sun 8/31

7:15 am-9:45 am

Nonstop4h 30m

$184

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Sat 8/23

11:10 pm-5:15 am

Nonstop4h 05m

Chicago Midway

Sun 8/31

8:20 pm-10:50 pm

Nonstop4h 30m

$184

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 8/23

8:10 am-5:55 pm

1 stop7h 45m

Chicago O'Hare Intl

Sun 8/31

7:30 am-2:50 pm

1 stop9h 20m

$203

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Tue 7/22

5:26 pm-11:33 pm

Nonstop4h 07m

Chicago O'Hare Intl

Sat 7/26

9:16 pm-11:59 pm

Nonstop4h 43m

$213

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/1

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 $321). 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 July 2, 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 July 2, 2025.

The most flights from SEA to USIL are scheduled on a Monday (82 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (27 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 July 2, 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
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Southwest
8.0
Very good
4,272 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Delta
8.0
Very good
7,983 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
Hawaiian Airlines
7.8
Good
2,540 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥
United Airlines
7.4
Good
8,861 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Overall

8.0

Food

7.1

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Reviews

1 / 20
8.0
Excellent

Anonymous,Aug 2024

SEA - LAS

Seats were not that comfy especially for someone with big hips 😥

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 Hawaiian Airlines ($87), Alaska Airlines ($88), and Delta ($90).

  • 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 Air France (100%), Austrian Airlines (93%) or Korean Air (88%) 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 $1,070 for a flight from Seattle to Illinois. The cheapest flight overall is $106 while the most popular route, (Seattle/Tacoma Intl - Chicago O'Hare Intl) is currently priced at $172.

  • 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 $321). 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

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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 July 2, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$107Average$189FlexibilityNo cancel feeOn-time65%
Hawaiian AirlinesCheapest$121Average$285FlexibilityNo cancel feeOn-time85%
DeltaCheapest$125Average$420FlexibilityNo cancel feeOn-timeN/A
FrontierCheapest$137Average$276FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$161Average$470FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$168Average$504FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$169Average$462FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$170Average$393FlexibilityNo cancel feeOn-time63%

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