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$88+ 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 5/13. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SEA
Apr 5 — Apr 121
Sat 4/5
Sat 4/12
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 March 31, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$169
(Alaska Airlines)

One-way from

$88
(Cheapflightsfares)

Popular in

July

Cheapest in

February

Average price

$319

Good round-trip deal

$267 or less

Good one-way deal

$153 or less
Provider with most accurate pricing for Chicago (CHI)-Seattle/Tacoma Intl flight deals.
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Provider most trusted by Cheapflights users for Chicago (CHI)-Seattle/Tacoma Intl flights.
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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. 18% potential increase in price ($62 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 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 March 31, 2025.

This Alaska Airlines deal was found by Cheapflights users on 3/31. 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.
Tue 5/136:00 amORD - SEA
Nonstop4h 30mAlaska Airlines
Sat 5/1711:40 pmSEA - ORD
Nonstop4h 00mAlaska Airlines
Deal found 3/31$169
This Delta deal was found by Cheapflights users on 3/30. 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 4/267:50 amORD - SEA
Nonstop4h 44mDelta
Sat 5/35:55 pmSEA - ORD
Nonstop4h 04mDelta
Deal found 3/30$171
This Mytrip deal was found by Cheapflights users on 3/31. 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.
Tue 4/295:36 amORD - SEA
2 stops31h 59mSpirit Airlines
Tue 5/612:30 pmSEA - ORD
1 stop20h 25mSpirit Airlines
Deal found 3/31$173
This United Airlines deal was found by Cheapflights users on 3/30. 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.
Sat 5/37:00 amORD - SEA
1 stop9h 00mUnited Airlines
Wed 5/711:59 pmSEA - ORD
Nonstop4h 01mUnited Airlines
Deal found 3/30$175
This Southwest deal was found by Cheapflights users on 3/31. 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.
Tue 4/292:20 pmMDW - SEA
1 stop11h 30mSouthwest
Tue 5/66:00 amSEA - MDW
Nonstop4h 10mSouthwest
Deal found 3/31$184
This Expedia deal was found by Cheapflights users on 3/30. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 5/86:00 amORD - SEA
Nonstop4h 30mMultiple Airlines
Tue 5/133:20 pmSEA - ORD
1 stop12h 05mMultiple Airlines
Deal found 3/30$192
This Kiwi.com deal was found by Cheapflights users on 3/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/169:00 pmORD - SEA
Nonstop4h 51mHawaiian Airlines
Tue 11/47:00 amSEA - ORD
Nonstop4h 04mHawaiian Airlines
Deal found 3/30$194
This Delta deal was found by Cheapflights users on 3/30. 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.
Tue 5/611:15 amSTL - SEA
1 stop8h 36mDelta
Sat 5/1011:50 pmSEA - STL
1 stop8h 57mDelta
Deal found 3/30$197
This American Airlines deal was found by Cheapflights users on 3/30. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/267:35 amORD - SEA
Nonstop4h 40mAmerican Airlines
Sat 5/311:59 pmSEA - ORD
Nonstop4h 05mAmerican Airlines
Deal found 3/30$201
This American Airlines deal was found by Cheapflights users on 3/29. 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 8/236:10 pmSTL - SEA
1 stop8h 34mAmerican Airlines
Sat 8/301:29 amSEA - STL
1 stop8h 30mAmerican Airlines
Deal found 3/29$214
This United Airlines deal was found by Cheapflights users on 3/30. 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.
Fri 5/26:11 pmSTL - SEA
1 stop8h 48mUnited Airlines
Sun 5/47:00 amSEA - STL
1 stop8h 07mUnited Airlines
Deal found 3/30$217
This Hawaiian Airlines deal was found by Cheapflights users on 3/30. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 4/236:30 amSTL - SEA
Nonstop4h 24mHawaiian Airlines
Tue 4/296:03 pmSEA - STL
Nonstop3h 56mHawaiian Airlines
Deal found 3/30$237

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 March 31, 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

Tue 4/22

9:00 am-11:32 am

Nonstop4h 32m

Seattle/Tacoma Intl

Tue 4/29

11:48 am-6:01 pm

Nonstop4h 13m

$169

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 4/26

7:50 am-10:34 am

Nonstop4h 44m

Seattle/Tacoma Intl

Sat 5/3

5:55 pm-11:59 pm

Nonstop4h 04m

$171

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Tue 4/29

5:36 am-11:35 am

2 stops31h 59m

Seattle/Tacoma Intl

Tue 5/6

12:30 pm-10:55 am

1 stop20h 25m

$173

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 5/3

7:00 am-2:00 pm

1 stop9h 00m

Seattle/Tacoma Intl

Wed 5/7

11:59 pm-6:00 am

Nonstop4h 01m

$175

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Tue 5/13

6:00 am-8:30 am

Nonstop4h 30m

Seattle/Tacoma Intl

Tue 5/20

9:00 am-11:56 pm

1 stop12h 56m

$179

ChicagoSeattle

MDW - SEA

MDWSEA

Chicago Midway

Tue 4/29

2:20 pm-11:50 pm

1 stop11h 30m

Seattle/Tacoma Intl

Tue 5/6

6:00 am-12:10 pm

Nonstop4h 10m

$184

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Tue 4/29

7:00 am-3:10 pm

1 stop10h 10m

Seattle/Tacoma Intl

Tue 5/6

5:00 am-2:00 pm

1 stop7h 00m

$194

St. LouisSeattle

STL - SEA

STLSEA

Lambert-St Louis

Tue 5/6

11:15 am-5:51 pm

1 stop8h 36m

Seattle/Tacoma Intl

Sat 5/10

11:50 pm-10:47 am

1 stop8h 57m

$197

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Sat 4/26

7:35 am-10:15 am

Nonstop4h 40m

Seattle/Tacoma Intl

Sat 5/3

11:59 pm-6:04 am

Nonstop4h 05m

$201

ChicagoSeattle

ORD - SEA

ORDSEA

Chicago O'Hare Intl

Fri 5/9

8:40 am-4:41 pm

1 stop10h 01m

Seattle/Tacoma Intl

Tue 5/13

3:20 pm-5:25 am

1 stop12h 05m

$202

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/30

Showing 1-10 of 58 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 July is currently the most expensive (average of $411). 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 March 31, 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 March 31, 2025.

The most flights from USIL to SEA are scheduled on a Monday (47 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (18 on average).

Rainfall in Seattle by month

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

In terms of precipitation, rainfall in Seattle ranges from 0.7 - 6.6 inches per month. November is typically the wettest month, when rainfall can reach 6.6 in. July is typically the driest time to visit Seattle when rainfall is around 0.7 in.

Temperature in Seattle by month

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

If weather is an important factor for your trip to Seattle, 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 66.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 41.0 F).

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 March 31, 2025.
See what other customers who have flown with Alaska Airlines, Southwest and Delta from Illinois to Seattle have to say. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
9,818 reviews

Comfort

7.9

Crew

8.5

Entertainment

7.1

Overall

8.0

Boarding

8.2

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very good
9,818 reviews
Alaska Airlines
8.0
Very good
9,818 reviews

Comfort

7.9

Crew

8.5

Entertainment

7.1

Overall

8.0

Boarding

8.2

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very good
4,276 reviews
Alaska Airlines
8.0
Very good
9,818 reviews

Comfort

7.9

Crew

8.5

Entertainment

7.1

Overall

8.0

Boarding

8.2

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very good
7,899 reviews
Alaska Airlines
8.0
Very good
9,818 reviews

Comfort

7.9

Crew

8.5

Entertainment

7.1

Overall

8.0

Boarding

8.2

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Hawaiian Airlines
7.9
Good
2,342 reviews
Alaska Airlines
8.0
Very good
9,818 reviews

Comfort

7.9

Crew

8.5

Entertainment

7.1

Overall

8.0

Boarding

8.2

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,614 reviews
Alaska Airlines
8.0
Very good
9,818 reviews

Comfort

7.9

Crew

8.5

Entertainment

7.1

Overall

8.0

Boarding

8.2

Food

7.1

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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 Spirit Airlines ($88), United Airlines ($90), and Southwest ($94).

  • 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: Air France (92%), Brussels Airlines (83%), Avianca (82%).

  • What are the cheapest flights from Illinois to Seattle?

    The cheapest flight price from Illinois to Seattle is $84. On average you can expect to pay $823. The most popular route, (Chicago O'Hare Intl - Seattle/Tacoma Intl), can usually be booked for $166.

  • 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 July is currently the most expensive (average of $411). 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 Illinois?

Book flights to Illinois if you plan to visit one of these locations
SeaTac
Tukwila
Tacoma
Lakewood
Renton
Lacey
Ocean Shores
Leavenworth
Federal Way
Olympia
Cle Elum
Centralia
Mukilteo
Aberdeen
Shoreline
Lynnwood
Shelton
Silverdale
Redmond
Monroe

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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 March 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
Hawaiian AirlinesCheapest$89Average$264FlexibilityNo cancel feeOn-time85%
FrontierCheapest$118Average$226FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$121Average$240FlexibilityNo cancel feeOn-time65%
Alaska AirlinesCheapest$139Average$507FlexibilityNo cancel feeOn-time75%
DeltaCheapest$140Average$359FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$151Average$506FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$168Average$469FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$197Average$408FlexibilityNo cancel feeOn-time63%
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