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$66+ 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 2/20. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Feb 23 — Mar 21
Mon 2/23
Mon 3/2
1 adult, Economy
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Cheap 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 January 24, 2026.

This WAYA deal was found by Cheapflights users on 1/22. 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 WAYA is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/191:16 pm
SEA
-
ORD
1 stop7h 58m
Multiple Airlines
Thu 2/263:54 pm
ORD
-
SEA
Nonstop4h 46m
Multiple Airlines
Deal found 1/22$164
This Kiwi.com deal was found by Cheapflights users on 1/24. 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.
Fri 3/66:00 am
SEA
-
ORD
Nonstop4h 01m
Hawaiian Airlines
Tue 3/107:00 am
ORD
-
SEA
Nonstop4h 51m
Hawaiian Airlines
Deal found 1/24$166
This Kiwi.com deal was found by Cheapflights users on 1/22. 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 2/166:00 am
SEA
-
ORD
Nonstop4h 01m
Hawaiian Airlines
Mon 2/235:29 pm
ORD
-
SEA
Nonstop4h 47m
Hawaiian Airlines
Deal found 1/22$167
This Kiwi.com deal was found by Cheapflights users on 1/24. 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.
Tue 3/105:55 pm
SEA
-
ORD
Nonstop4h 01m
Hawaiian Airlines
Tue 3/177:00 am
ORD
-
SEA
Nonstop4h 51m
Hawaiian Airlines
Deal found 1/24$168
This Kiwi.com deal was found by Cheapflights users on 1/22. 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 2/166:00 am
SEA
-
ORD
Nonstop4h 01m
Hawaiian Airlines
Tue 2/245:29 pm
ORD
-
SEA
Nonstop4h 47m
Hawaiian Airlines
Deal found 1/22$169
This Kiwi.com deal was found by Cheapflights users on 1/23. 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.
Sun 2/229:23 pm
SEA
-
ORD
1 stop18h 46m
Frontier
Sun 3/14:16 pm
ORD
-
SEA
1 stop21h 03m
Frontier
Deal found 1/23$172
This Trip.com deal was found by Cheapflights users on 1/22. 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.
Thu 3/2612:35 am
SEA
-
ORD
Nonstop4h 04m
Multiple Airlines
Tue 3/318:00 am
ORD
-
SEA
Nonstop4h 43m
Multiple Airlines
Deal found 1/22$173
This Southwest deal was found by Cheapflights users on 1/24. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 3/72:45 pm
SEA
-
MDW
1 stop5h 35m
Southwest
Sat 3/149:40 pm
MDW
-
SEA
Nonstop4h 35m
Southwest
Deal found 1/24$174
This Kissandfly.com deal was found by Cheapflights users on 1/23. 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 Kissandfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/1912:07 am
SEA
-
ORD
Nonstop4h 16m
Hawaiian Airlines
Sat 2/287:00 am
ORD
-
SEA
Nonstop4h 51m
Hawaiian Airlines
Deal found 1/23$176
This American Airlines deal was found by Cheapflights users on 1/22. 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.
Thu 3/2612:13 am
SEA
-
ORD
Nonstop4h 16m
American Airlines
Wed 4/19:40 pm
ORD
-
SEA
Nonstop4h 44m
American Airlines
Deal found 1/22$177
This Southwest deal was found by Cheapflights users on 1/23. 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 2/207:25 am
SEA
-
MDW
Nonstop4h 05m
Southwest
Sat 2/2811:10 am
MDW
-
SEA
Nonstop4h 40m
Southwest
Deal found 1/23$177
This Alaska Airlines deal was found by Cheapflights users on 1/21. 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.
Fri 2/275:55 pm
SEA
-
ORD
Nonstop4h 01m
Alaska Airlines
Mon 3/23:54 pm
ORD
-
SEA
Nonstop4h 46m
Alaska Airlines
Deal found 1/21$178

Find flight deals from Seattle to Illinois

Keep the following information in mind while searching for Seattle to Illinois flight deals. Data was last updated January 24, 2026.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$164
(WAYA)

One-way from

$66
(Kiwi.com)

Popular in

December

Cheapest in

February

Average price

$267

Good round-trip deal

$288 or less

Good one-way deal

$140 or less
Provider with most accurate pricing for Seattle/Tacoma Intl-Chicago (CHI) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Seattle/Tacoma Intl-Chicago (CHI) flights.
Search Deals
From Seattle/Tacoma Intl to Illinois
Search Deals
One-way flight from Seattle/Tacoma Intl to Illinois
Search Deals
Highest demand for flights based on searches. 6% potential increase in price ($22 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 2026
Search Deals
Price to beat on a round-trip flight from Seattle/Tacoma Intl to Illinois.
Search Deals
Price to beat on a one-way flight from Seattle/Tacoma Intl to Illinois.
Search Deals

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 January 24, 2026.
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 3/7

5:55 pm-11:52 pm

Nonstop3h 57m

Chicago O'Hare Intl

Tue 3/10

2:20 pm-4:58 pm

Nonstop4h 38m

$177

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Tue 2/24

7:00 am-1:06 pm

Nonstop4h 06m

Chicago O'Hare Intl

Wed 2/25

7:59 pm-10:43 pm

Nonstop4h 44m

$177

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Mon 3/9

11:55 pm-5:50 am

Nonstop3h 55m

Chicago Midway

Tue 3/10

9:20 pm-11:55 pm

Nonstop4h 35m

$177

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Thu 3/5

7:10 am-1:22 pm

Nonstop4h 12m

Chicago O'Hare Intl

Tue 3/10

2:20 pm-4:58 pm

Nonstop4h 38m

$177

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Fri 2/20

7:00 am-1:06 pm

Nonstop4h 06m

Chicago O'Hare Intl

Fri 2/27

4:20 pm-7:03 pm

Nonstop4h 43m

$177

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Fri 3/13

11:55 pm-5:50 am

Nonstop3h 55m

Chicago Midway

Sun 3/15

9:45 pm-12:20 am

Nonstop4h 35m

$177

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Wed 3/4

5:55 pm-11:52 pm

Nonstop3h 57m

Chicago O'Hare Intl

Sun 3/8

7:25 am-10:03 am

Nonstop4h 38m

$177

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Fri 2/20

7:25 am-1:30 pm

Nonstop4h 05m

Chicago Midway

Sat 2/28

11:10 am-1:50 pm

Nonstop4h 40m

$177

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 3/7

5:55 pm-11:52 pm

Nonstop3h 57m

Chicago O'Hare Intl

Mon 3/9

7:25 am-10:03 am

Nonstop4h 38m

$177

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Sun 3/15

11:55 pm-5:50 am

Nonstop3h 55m

Chicago Midway

Sat 3/28

9:40 pm-12:15 am

Nonstop4h 35m

$177

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/22

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, January is the cheapest month in which you can book a flight from Seattle to Illinois (average of $112). 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 January 24, 2026.

It’s typically best to fly out from Seattle to Illinois in the evening. Doing so could potentially save you 7% 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 January 17, 2026.

Travelers seeking maximum savings on their Seattle to Illinois flight should consider departing on Saturday afternoons when fares are most often at their lowest. Sunday 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 January 24, 2026.

The most flights from SEA to USIL are scheduled on a Friday (41 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (28 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 January 24, 2026.
Read through reviews of airlines operating flights from Seattle to Illinois, such as Alaska Airlines, Delta, and Hawaiian Airlines. 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
11,785 reviews

Entertainment

7.0

Food

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
Alaska Airlines
8.0
Very good
11,785 reviews
Alaska Airlines
8.0
Very good
11,785 reviews

Entertainment

7.0

Food

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
Delta
7.9
Good
8,110 reviews
Alaska Airlines
8.0
Very good
11,785 reviews

Entertainment

7.0

Food

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
Hawaiian Airlines
7.8
Good
2,829 reviews
Alaska Airlines
8.0
Very good
11,785 reviews

Entertainment

7.0

Food

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
United Airlines
7.4
Good
9,194 reviews
Alaska Airlines
8.0
Very good
11,785 reviews

Entertainment

7.0

Food

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.
American Airlines
7.2
Good
11,192 reviews
Alaska Airlines
8.0
Very good
11,785 reviews

Entertainment

7.0

Food

7.1

Boarding

8.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
4.0
Okay

Anonymous,Dec 2025

SEA - MSY

I really got a lesson in upgrades. I let my seat get chosen . Both times a middle seat...on purpose ...even when we were not full. That's petty I sat behind the first class . They got more than 1 drink ...and a snack . .and the staff actually talked to them...behind a see thru shawl/sheet in the aisle....... You could see over the seats just fine and you could hear the voices just fine. But the sheet let You KNOW. Your not welcome here. For a moment I regretted not spending 300 dollars per seat so I could see a smile and eat a sandwhich and enjoy my seat . The married couple drank champain and laughed and flirted with each other. It looked so happy and care free MONEY really does buy happiness ..the hateful glares and sighs from my seat mates brought me back to reality I wasn't rich and I still had 2 hours left in this middle seat.

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 Delta, United Airlines, and Southwest fly from Seattle to Illinois in about 3h 55m. The time it takes to get you to your destination is usually consistent. The distance between Seattle and Illinois is about 1728 mi. Most flights are nonstop.

  • 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 Frontier ($70), Southwest ($84), and Alaska Airlines ($84).

  • 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 (88%), Gulf Air (85%) or Alaska Airlines (85%) 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 $708 for a flight from Seattle to Illinois. The cheapest flight overall is $94 while the most popular route, (Seattle/Tacoma Intl - Chicago O'Hare Intl) is currently priced at $166.

  • 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, January is the cheapest month in which you can book a flight from Seattle to Illinois (average of $112). 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.

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Alternative routes for Seattle to Illinois

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Top 7 airlines flying from Seattle to Illinois

Discover the top 7 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 January 24, 2026.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$97Average$289FlexibilityNo cancel feeOn-timeN/A
Hawaiian AirlinesCheapest$114Average$258FlexibilityNo cancel feeOn-time85%
FrontierCheapest$137Average$271FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$154Average$419FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$169Average$503FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$178Average$443FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$184Average$358FlexibilityNo cancel feeOn-time63%

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