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$84+ Cheap flights from Illinois to Seattle (SEA)

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 9/9. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SEA
Jul 30 — Aug 61
Wed 7/30
Wed 8/6
1 adult, Economy
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Cheap flight deals from Illinois to Seattle

Keep the following information in mind while searching for Illinois to Seattle flight deals. Data was last updated July 25, 2025.

Round-trip from

$176
(SmartFares)

One-way from

$84
(United Airlines)

Popular in

December

Cheapest in

February

Average price

$329

Good round-trip deal

$197 or less

Good one-way deal

$124 or less
From Illinois to Seattle/Tacoma Intl
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One-way flight from Illinois to Seattle/Tacoma Intl
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Highest demand for flights based on searches. 5% potential increase in price ($15 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 Illinois to Seattle/Tacoma Intl.
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Price to beat on a one-way flight from Illinois to Seattle/Tacoma Intl.
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Find flight deals from Illinois to Seattle

Cheapest flights from Illinois to Seattle
Explore the most affordable flight options available from Illinois to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 25, 2025.

This SmartFares deal was found by Cheapflights users on 7/24. 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 SmartFares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/108:00 amORD - SEA
Nonstop4h 37mHawaiian Airlines
Tue 9/1612:59 amSEA - ORD
Nonstop4h 04mHawaiian Airlines
Deal found 7/24$176
This SmartFares deal was found by Cheapflights users on 7/24. 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 SmartFares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/106:20 amORD - SEA
Nonstop4h 32mAlaska Airlines
Tue 9/1612:59 amSEA - ORD
Nonstop4h 04mAlaska Airlines
Deal found 7/24$180
This Southwest deal was found by Cheapflights users on 7/23. 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.
Sat 10/259:15 amMDW - SEA
Nonstop4h 35mSouthwest
Fri 10/315:45 amSEA - MDW
Nonstop4h 00mSouthwest
Deal found 7/23$184
This American Airlines deal was found by Cheapflights users on 7/22. 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.
Sat 8/236:50 amORD - SEA
Nonstop4h 29mAmerican Airlines
Sat 8/303:09 pmSEA - ORD
Nonstop4h 05mAmerican Airlines
Deal found 7/22$185
This Kiwi.com deal was found by Cheapflights users on 7/24. 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.
Sun 8/312:07 pmORD - SEA
1 stop6h 38mMultiple Airlines
Tue 9/93:59 pmSEA - ORD
Nonstop4h 08mMultiple Airlines
Deal found 7/24$187
This Delta deal was found by Cheapflights users on 7/24. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/306:13 pmORD - SEA
Nonstop4h 37mDelta
Sat 9/65:50 pmSEA - ORD
Nonstop4h 01mDelta
Deal found 7/24$190
This United Airlines deal was found by Cheapflights users on 7/23. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/67:10 amORD - SEA
Nonstop4h 33mUnited Airlines
Tue 9/98:00 amSEA - ORD
1 stop8h 25mUnited Airlines
Deal found 7/23$195
This Southwest deal was found by Cheapflights users on 7/24. 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 8/304:20 pmORD - SEA
1 stop8h 10mSouthwest
Sat 9/68:10 amSEA - ORD
1 stop7h 45mSouthwest
Deal found 7/24$208
This American Airlines deal was found by Cheapflights users on 7/23. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/82:12 pmSPI - SEA
1 stop8h 34mAmerican Airlines
Wed 10/152:52 pmSEA - SPI
1 stop6h 26mAmerican Airlines
Deal found 7/23$239
This FlightHub deal was found by Cheapflights users on 7/23. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/262:44 pmMDW - SEA
1 stop10h 58mFrontier
Sat 8/26:25 amSEA - MDW
1 stop12h 29mFrontier
Deal found 7/23$245
This Hawaiian Airlines deal was found by Cheapflights users on 7/24. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/216:30 pmSTL - SEA
Nonstop4h 24mHawaiian Airlines
Mon 8/256:03 pmSEA - STL
Nonstop3h 56mHawaiian Airlines
Deal found 7/24$247
This CheapOair deal was found by Cheapflights users on 7/24. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/207:54 pmSTL - SEA
1 stop15h 40mFrontier
Sun 8/244:40 pmSEA - STL
1 stop14h 31mFrontier
Deal found 7/24$249

Cheapflights Fare Finder

 
Customize your flight search to find flights from Illinois to Seattle 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 25, 2025.
Use the filters below to find and compare flights from Illinois to Seattle that are best for you.

Fly from

Illinois

Fly to

Seattle

Route

Depart

Return

Price

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Wed 9/10

8:00 am-10:37 am

Nonstop4h 37m

Seattle/Tacoma Intl

Tue 9/16

12:59 am-7:03 am

Nonstop4h 04m

$176

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Wed 9/10

6:20 am-8:52 am

Nonstop4h 32m

Seattle/Tacoma Intl

Tue 9/16

12:59 am-7:03 am

Nonstop4h 04m

$180

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 8/23

6:50 am-9:19 am

Nonstop4h 29m

Seattle/Tacoma Intl

Sat 8/30

3:09 pm-9:14 pm

Nonstop4h 05m

$185

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 9/13

3:20 pm-5:52 pm

Nonstop4h 32m

Seattle/Tacoma Intl

Mon 9/15

12:59 am-7:03 am

Nonstop4h 04m

$187

ChicagoSeattle

MDW - SEA

MDWSEA

Chicago Midway

Sat 9/6

5:25 pm-7:55 pm

Nonstop4h 30m

Seattle/Tacoma Intl

Tue 9/9

5:35 am-11:30 am

Nonstop3h 55m

$189

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 8/30

6:13 pm-8:50 pm

Nonstop4h 37m

Seattle/Tacoma Intl

Sat 9/6

5:50 pm-11:51 pm

Nonstop4h 01m

$190

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 9/6

7:10 am-9:43 am

Nonstop4h 33m

Seattle/Tacoma Intl

Tue 9/9

8:00 am-6:25 pm

1 stop8h 25m

$195

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 8/30

4:20 pm-10:30 pm

1 stop8h 10m

Seattle/Tacoma Intl

Sat 9/6

8:10 am-5:55 pm

1 stop7h 45m

$208

SpringfieldSeattle

SPI - SEA

SPISEA

Springfield Capital

Wed 10/8

2:12 pm-8:46 pm

1 stop8h 34m

Seattle/Tacoma Intl

Wed 10/15

2:52 pm-11:18 pm

1 stop6h 26m

$239

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Thu 8/21

6:30 pm-8:54 pm

Nonstop4h 24m

Seattle/Tacoma Intl

Mon 8/25

6:03 pm-11:59 pm

Nonstop3h 56m

$247

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/24

Showing 1-10 of 57 results
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Best time to book a flight from Illinois to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Illinois 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 Illinois to Seattle

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

Currently, January is the cheapest month in which you can book a flight from Illinois to Seattle (average of $238). Flying from Illinois to Seattle in June is currently the most expensive (average of $389). 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 IL to SEA?

Find hourly flight availability from Illinois to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated July 25, 2025.

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

Weekly flight availability from Illinois to Seattle

Explore weekly flight availability from Illinois to Seattle. 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 25, 2025.

The most flights from USIL to SEA are scheduled on a Thursday (70 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (37 on average).

Reviews of airlines servicing Seattle

Get insights into the airlines that provide service to Seattle. 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 Seattle. Reviews last updated July 25, 2025.
Get a feel of what it's like to fly with Alaska Airlines, Southwest, and Delta from Illinois to Seattle by reading reviews from past customers. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Southwest
8.0
Very good
4,235 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Delta
8.0
Very good
7,967 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Hawaiian Airlines
7.8
Good
2,595 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
United Airlines
7.4
Good
8,880 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Overall

8.0

Food

7.1

Boarding

8.1

Crew

8.5

Entertainment

7.1

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.

Related info for your journey

Find useful and relevant information for your journey from Illinois to Seattle. 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 into for flights to Seattle from Illinois?

    Seattle/Tacoma Intl (SEA), located 11.4 mi from the city center, is the airport you fly into when you book flights from Illinois to Seattle.

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

    The cheapest airlines for a one-way flight from Illinois to Seattle are United Airlines ($84), Delta ($89), and Southwest ($104).

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

    The most popular route from Illinois to Seattle is Chicago O'Hare Intl - Seattle/Tacoma Intl. You may also consider Lambert-St Louis - Seattle/Tacoma Intl or Chicago Midway - Seattle/Tacoma Intl.

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

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Illinois to Seattle on time: KLM (100%), Air France (86%), Delta (85%).

  • What are the cheapest flights from Illinois to Seattle?

    The cheapest flight price from Illinois to Seattle is $94. On average you can expect to pay $744. The most popular route, (Chicago O'Hare Intl - Seattle/Tacoma Intl), can usually be booked for $173.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Illinois to Seattle 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 Illinois to Seattle?

    Currently, January is the cheapest month in which you can book a flight from Illinois to Seattle (average of $238). Flying from Illinois to Seattle in June is currently the most expensive (average of $389). 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

Traveling to a place near Seattle?

Book flights to Seattle if you plan to visit one of these locations
SeaTac
Tukwila
Tacoma
Ocean Shores
Lakewood
Lynnwood
Lacey
Leavenworth
Renton
Olympia
Puyallup
Kent
Cle Elum
Chehalis
Kirkland
Issaquah
Aberdeen
Shoreline
Federal Way
Shelton

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Alternative routes for Illinois to Seattle

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

Discover the top 8 airlines that operate flights from Illinois to Seattle. 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 25, 2025.
AirlineCheapestAverageFlexibilityOn-time
Hawaiian AirlinesCheapest$90Average$250FlexibilityNo cancel feeOn-time85%
Spirit AirlinesCheapest$98Average$209FlexibilityNo cancel feeOn-time65%
FrontierCheapest$118Average$233FlexibilityNo cancel feeOn-time62%
DeltaCheapest$123Average$287FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$156Average$479FlexibilityNo cancel feeOn-time75%
United AirlinesCheapest$166Average$469FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$168Average$448FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$194Average$410FlexibilityNo cancel feeOn-time63%

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