HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Illinois

$94+ 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 1/23. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Dec 30 — Jan 61
Mon 12/30
Mon 1/6
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Seattle to Illinois with Cheapflights

1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”
2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.
3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from Seattle to Illinois

Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Illinois (USIL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated December 25, 2024.

Round-trip from

$181
(FlightHub)

One-way from

$94
(Delta)
From Seattle/Tacoma Intl to Illinois
Search Deals
One-way flight from Seattle/Tacoma Intl to Illinois
Search Deals

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 December 25, 2024.

This American Airlines deal was found by Cheapflights users on 12/23. 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.
Tue 12/3112:31 amSEA - ORD
Nonstop4h 03mAmerican Airlines
Thu 1/99:55 amORD - SEA
Nonstop4h 47mAmerican Airlines
Deal found 12/23$209
This Frontier deal was found by Cheapflights users on 12/23. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/269:36 pmSEA - STL
1 stop8h 37mFrontier
Thu 1/308:31 pmSTL - SEA
1 stop14h 19mFrontier
Deal found 12/23$264
This Delta deal was found by Cheapflights users on 12/24. 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.
Tue 12/315:55 pmSEA - ORD
Nonstop4h 04mDelta
Tue 1/77:15 amORD - SEA
Nonstop4h 56mDelta
Deal found 12/24$267
This American Airlines deal was found by Cheapflights users on 12/23. 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.
Tue 12/3112:31 amSEA - STL
1 stop7h 05mAmerican Airlines
Wed 1/82:27 pmSTL - SEA
1 stop7h 33mAmerican Airlines
Deal found 12/23$273
This Alaska Airlines deal was found by Cheapflights users on 12/24. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/318:45 pmSEA - ORD
1 stop6h 45mAlaska Airlines
Tue 1/76:55 pmORD - SEA
Nonstop4h 51mAlaska Airlines
Deal found 12/24$297
This Orbitz deal was found by Cheapflights users on 12/23. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/269:36 pmSEA - STL
1 stop8h 37mMultiple Airlines
Thu 1/302:49 pmSTL - SEA
Nonstop4h 41mMultiple Airlines
Deal found 12/23$324
This FlightHub deal was found by Cheapflights users on 12/24. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/316:11 amSEA - ORD
1 stop13h 13mSpirit Airlines
Tue 1/79:54 pmORD - SEA
1 stop17h 17mSpirit Airlines
Deal found 12/24$333
This Gotogate deal was found by Cheapflights users on 12/24. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/309:36 pmSEA - ORD
1 stop13h 44mFrontier
Sun 1/51:07 pmORD - SEA
1 stop26h 03mFrontier
Deal found 12/24$352
This FlightHub deal was found by Cheapflights users on 12/24. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/309:36 pmSEA - ORD
1 stop13h 44mMultiple Airlines
Sat 1/48:52 amORD - SEA
1 stop17h 18mMultiple Airlines
Deal found 12/24$379
This Southwest deal was found by Cheapflights users on 12/23. 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.
Thu 12/268:00 amSEA - STL
1 stop10h 15mSouthwest
Thu 1/302:50 pmSTL - SEA
2 stops9h 40mSouthwest
Deal found 12/23$443
This Alaska Airlines deal was found by Cheapflights users on 12/25. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/316:04 pmSEA - STL
Nonstop3h 55mAlaska Airlines
Fri 1/37:00 amSTL - SEA
Nonstop4h 38mAlaska Airlines
Deal found 12/25$447
This United deal was found by Cheapflights users on 12/24. 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 United is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/3112:32 pmSEA - ORD
1 stop8h 49mUnited Airlines
Tue 1/710:49 amORD - SEA
2 stops12h 31mUnited Airlines
Deal found 12/24$477

Find flights from Seattle to Illinois within your budget

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 December 25, 2024.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Sat 1/18

9:45 am-9:52 pm

1 stop10h 07m

Chicago O'Hare Intl

Sun 1/26

6:36 pm-8:50 am

1 stop16h 14m

$181

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Wed 1/22

9:45 am-5:31 am

1 stop17h 46m

Chicago O'Hare Intl

Wed 1/29

1:39 pm-12:19 am

1 stop12h 40m

$183

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Thu 2/6

6:10 pm-12:11 am

Nonstop4h 01m

Chicago O'Hare Intl

Thu 2/13

7:00 am-9:58 am

Nonstop4h 58m

$187

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Fri 1/31

10:40 am-4:40 pm

Nonstop4h 00m

Chicago Midway

Sun 2/2

5:35 pm-8:10 pm

Nonstop4h 35m

$187

SeattleChicago

SEA - MDW

SEAMDW

Seattle/Tacoma Intl

Thu 1/23

3:15 pm-12:17 am

1 stop7h 02m

Chicago Midway

Thu 1/30

7:15 am-3:35 pm

1 stop10h 20m

$188

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Tue 4/15

11:36 pm-5:40 am

Nonstop4h 04m

Chicago O'Hare Intl

Tue 4/22

9:00 am-11:32 am

Nonstop4h 32m

$189

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Thu 2/20

7:05 am-1:14 pm

Nonstop4h 09m

Chicago O'Hare Intl

Thu 2/20

7:59 pm-10:42 pm

Nonstop4h 43m

$191

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Fri 1/24

1:35 pm-7:40 pm

Nonstop4h 05m

Chicago O'Hare Intl

Tue 1/28

3:20 pm-10:43 pm

1 stop9h 23m

$218

SeattleChicago

SEA - ORD

SEAORD

Seattle/Tacoma Intl

Mon 2/17

3:16 pm-12:44 am

1 stop7h 28m

Chicago O'Hare Intl

Wed 2/19

6:50 am-12:36 pm

1 stop7h 46m

$240

SeattleSt. Louis

SEA - STL

SEASTL

Seattle/Tacoma Intl

Fri 2/28

6:11 pm-11:59 pm

Nonstop3h 48m

Lambert-St Louis

Tue 3/4

7:00 am-9:35 am

Nonstop4h 35m

$247

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/24

Showing 1-10 of 55 results
1
2
3
...
6

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.

Travel insights for flights from Seattle to Illinois

Get recent, data-driven insights about flights from Seattle to Illinois including ideal travel times, pricing trends, and more.

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 $317). 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 December 25, 2024.

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 December 25, 2024.

The most flights from SEA to USIL are scheduled on a Monday (40 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (17 on average).

Rainfall in Illinois by month

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

In terms of precipitation, rainfall in Illinois ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Illinois when rainfall is around 1.7 in.

Temperature in Illinois by month

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

If weather is an important factor for your trip to Illinois, 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 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).

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 December 25, 2024.
Read reviews from past customers who have flown Delta, Alaska Airlines and United Airlines from Seattle to Illinois. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,758 reviews

Entertainment

7.7

Overall

8.1

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very good
4,758 reviews
Southwest
8.1
Very good
4,758 reviews

Entertainment

7.7

Overall

8.1

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Alaska Airlines
8.0
Very good
9,554 reviews
Southwest
8.1
Very good
4,758 reviews

Entertainment

7.7

Overall

8.1

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very good
8,580 reviews
Southwest
8.1
Very good
4,758 reviews

Entertainment

7.7

Overall

8.1

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

JetBlue
7.4
Good
3,249 reviews
Southwest
8.1
Very good
4,758 reviews

Entertainment

7.7

Overall

8.1

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
9,007 reviews
Southwest
8.1
Very good
4,758 reviews

Entertainment

7.7

Overall

8.1

Comfort

8.1

Crew

8.7

Boarding

8.2

Food

7.2

Reviews

1 / 10

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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 Delta ($94), Southwest ($94), and United Airlines ($95).

  • 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 WestJet (100%), Avianca (94%) or Royal Jordanian (94%) 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 $870 for a flight from Seattle to Illinois. The cheapest flight overall is $98 while the most popular route, (Seattle/Tacoma Intl - Chicago O'Hare Intl) is currently priced at $136.

  • 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 $317). 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Seattle to Illinois

See prices for flight routes from nearby airports that may be better suited for you.
Seattle to Sky Harbor Intl flights
Seattle to Los Angeles flights
Seattle to Las Vegas flights
Seattle to Honolulu flights
Seattle to Newark flights
Seattle to John F Kennedy Intl flights
Seattle to San Diego flights
Seattle to Ontario flights
Portland to Los Angeles flights
Seattle to Santa Ana flights
Seattle to Kahului flights
Seattle to Hobby flights
Seattle to Dallas/Fort Worth flights
Seattle to Denver flights
Seattle to Miami flights
Seattle to San Francisco flights
Portland to Las Vegas flights
Seattle to Orlando flights
Seattle to O'Hare Intl flights
Seattle to LaGuardia flights
Seattle to Kailua-Kona flights
Seattle to George Bush Intcntl flights
Seattle to Burbank flights
Seattle to New Orleans flights
Seattle to Palm Springs flights
Seattle to Dulles Intl flights
Portland to Honolulu flights
Seattle to Lihue flights
Seattle to Atlanta flights
Seattle to Fort Lauderdale flights
Everett to Las Vegas flights
Seattle to Salt Lake City flights
Seattle to Reagan-National flights
Seattle to Tampa flights
Portland to John F Kennedy Intl flights
Seattle to Minneapolis flights
Seattle to Boston flights
Seattle to Nashville flights
Portland to Sky Harbor Intl flights
Portland to Denver flights
Seattle to Baltimore flights
Seattle to Austin flights
Portland to Dallas/Fort Worth flights
Portland to Newark flights
Everett to Los Angeles flights
Portland to Santa Ana flights
Seattle to San Jose flights
Portland to Kailua-Kona flights
Portland to Kahului flights
Seattle to Tucson flights

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 December 25, 2024.
AirlineCheapestAverageFlexibilityOn-time
DeltaCheapest$102Average$443FlexibilityNo cancel feeOn-timeN/A
Spirit AirlinesCheapest$115Average$242FlexibilityNo cancel feeOn-time65%
FrontierCheapest$128Average$257FlexibilityNo cancel feeOn-time62%
Alaska AirlinesCheapest$128Average$526FlexibilityNo cancel feeOn-time75%
American AirlinesCheapest$140Average$509FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$152Average$548FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$179Average$399FlexibilityNo cancel feeOn-time63%
100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.