$85+ 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 7/8. Fares are subject to change and may not be available on all flights or dates of travel.
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
Keep the following information in mind while searching for Seattle to Illinois flight deals. Data was last updated April 17, 2025.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | Flightnetwork 3 stars |
Round-trip from | $172 (Trip.com) |
One-way from | $85 (Alaska Airlines) |
Popular in | December |
Cheapest in | January |
Average price | $283 |
Good round-trip deal | $302 or less |
Good one-way deal | $167 or less |
Find flight deals from Seattle to Illinois
Cheapest flights from Seattle to IllinoisExplore 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 April 17, 2025.
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 April 17, 2025.
This Trip.com deal was found by Cheapflights users on 4/17. 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.
This Trip.com deal was found by Cheapflights users on 4/17. 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.
This Frontier deal was found by Cheapflights users on 4/17. 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.
This Alaska Airlines deal was found by Cheapflights users on 4/17. 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.
This CheapOair deal was found by Cheapflights users on 4/17. 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.
This Southwest deal was found by Cheapflights users on 4/16. 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.
This Delta deal was found by Cheapflights users on 4/17. 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.
This Cheapflightsfares deal was found by Cheapflights users on 4/17. 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.
This CheapOair deal was found by Cheapflights users on 4/17. 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.
This Delta deal was found by Cheapflights users on 4/17. 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.
This Southwest deal was found by Cheapflights users on 4/16. 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.
This United Airlines deal was found by Cheapflights users on 4/17. 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.
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 April 17, 2025.
Use the filters below to find and compare flights from Seattle to Illinois that are best for you.
Fly from
Fly to
Route
Depart
Return
Price
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Wed 5/7
3:58 pm-9:59 pm
Nonstop4h 01m
Chicago O'Hare Intl
Wed 5/14
9:00 am-11:32 am
Nonstop4h 32m
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Wed 5/7
10:48 am-5:00 pm
Nonstop4h 12m
Chicago O'Hare Intl
Wed 5/14
9:00 am-11:32 am
Nonstop4h 32m
SeattleChicago
SEA - MDW
SEAMDW
Seattle/Tacoma Intl
Sat 5/24
6:25 am-8:53 pm
1 stop12h 28m
Chicago Midway
Sat 5/31
2:44 pm-12:37 am
1 stop11h 53m
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Wed 5/21
2:00 pm-11:56 pm
1 stop7h 56m
Chicago O'Hare Intl
Sat 5/24
7:51 pm-10:30 pm
Nonstop4h 39m
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Sat 5/24
6:25 am-11:52 pm
1 stop15h 27m
Chicago O'Hare Intl
Sat 5/31
6:00 am-12:37 am
1 stop20h 37m
SeattleChicago
SEA - MDW
SEAMDW
Seattle/Tacoma Intl
Tue 6/10
10:55 pm-5:00 am
Nonstop4h 05m
Chicago Midway
Sat 6/14
9:40 pm-12:15 am
Nonstop4h 35m
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Fri 5/9
11:15 am-5:25 pm
Nonstop4h 10m
Chicago O'Hare Intl
Tue 5/13
6:20 pm-8:50 pm
Nonstop4h 30m
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Sat 5/17
3:20 pm-5:25 am
1 stop12h 05m
Chicago O'Hare Intl
Wed 5/21
11:50 am-12:10 am
1 stop14h 20m
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Sun 5/4
6:00 am-9:09 am
1 stop25h 09m
Lambert-St Louis
Sun 5/11
9:55 pm-6:00 pm
1 stop22h 05m
SeattleSt. Louis
SEA - STL
SEASTL
Seattle/Tacoma Intl
Fri 5/9
11:50 pm-10:52 am
1 stop9h 02m
Lambert-St Louis
Tue 5/13
7:19 pm-11:59 pm
1 stop6h 40m
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.
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 April 17, 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 April 17, 2025.
The most flights from SEA to USIL are scheduled on a Thursday (59 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (31 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 April 17, 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest and Delta 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.
Entertainment
Boarding
Crew
Overall
Comfort
Food
Reviews
Anonymous,Aug 2024
SEA - LAS
Entertainment
Boarding
Crew
Overall
Comfort
Food
Reviews
Anonymous,Aug 2024
SEA - LAS
Entertainment
Boarding
Crew
Overall
Comfort
Food
Reviews
Anonymous,Aug 2024
SEA - LAS
Entertainment
Boarding
Crew
Overall
Comfort
Food
Reviews
Anonymous,Aug 2024
SEA - LAS
Entertainment
Boarding
Crew
Overall
Comfort
Food
Reviews
Anonymous,Aug 2024
SEA - LAS
Entertainment
Boarding
Crew
Overall
Comfort
Food
Reviews
Anonymous,Aug 2024
SEA - LAS
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.
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Alternative routes for Seattle to Illinois
See prices for flight routes from nearby airports that may be better suited for you.
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 April 17, 2025.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$107 | Average$213 | FlexibilityNo cancel fee | On-time65% | |
| Cheapest$119 | Average$279 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$125 | Average$437 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$137 | Average$246 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$158 | Average$496 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$158 | Average$484 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$166 | Average$534 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$200 | Average$398 | FlexibilityNo cancel fee | On-time63% |