$82 Find Cheap Flights from Seattle to Illinois

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Seattle to Illinois departing on 5/26. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to Illinois

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Illinois.
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Seattle to Illinois.
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Flight Deals

Cheap Flights from Seattle to Illinois

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Chicago
Chicago1 stop$236
Moline
Moline1 stop$349
Peoria
Peoria1 stop$271
Bloomington
Bloomington1 stop$343
Champaign
Champaign1 stop$306
Springfield
Springfield1 stop$515
St. Louis
St. Louis1 stop$291
Decatur
Decatur1 stop$444
Paducah
Paducah1 stop$475
Chicago
Chicago1 stop$236
Moline
Moline1 stop$349
Peoria
Peoria1 stop$271
Bloomington
Bloomington1 stop$343
Champaign
Champaign1 stop$306
Springfield
Springfield1 stop$515
St. Louis
St. Louis1 stop$291
Decatur
Decatur1 stop$444
Paducah
Paducah1 stop$475

Book Cheap Seattle to Illinois Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Seattle to Illinois that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Seattle to Illinois

Mon, May 18 - Tue, May 19
Frontier Logo
11:06 am - 6:39 am
SEA
-
ORD
17h 33m
1 stop
Frontier Logo
8:56 pm - 6:35 pm
ORD
-
SEA
23h 39m
1 stop
$236Frontier
Sun, May 10 - Wed, May 13
Frontier Logo
7:50 pm - 8:32 pm
SEA
-
ORD
22h 42m
1 stop
Frontier Logo
9:37 pm - 9:49 am
ORD
-
SEA
14h 12m
1 stop
$237Frontier
Wed, Aug 26 - Sat, Aug 29
American Airlines Logo
5:05 am - 3:53 pm
SEA
-
PIA
8h 48m
1 stop
American Airlines Logo
6:45 pm - 11:59 pm
PIA
-
SEA
7h 14m
1 stop
$271American Airlines
Tue, May 19 - Tue, Jun 9
American Airlines Logo
7:10 am - 6:24 pm
SEA
-
CMI
9h 14m
1 stop
American Airlines Logo
6:43 pm - 12:41 am
CMI
-
SEA
7h 58m
1 stop
$306American Airlines
Wed, Aug 26 - Sat, Aug 29
United Airlines Logo
12:29 pm - 12:22 am
SEA
-
PIA
9h 53m
2 stops
United Airlines Logo
5:31 pm - 10:42 pm
PIA
-
SEA
7h 11m
1 stop
$313United Airlines
Sat, May 16 - Sat, Jun 6
United Airlines Logo
7:00 am - 4:50 pm
SEA
-
PIA
7h 50m
1 stop
United Airlines Logo
5:33 pm - 11:59 pm
PIA
-
SEA
8h 26m
1 stop
$316United Airlines
Sun, May 10 - Wed, May 13
Southwest Logo
11:55 pm - 5:55 am
SEA
-
MDW
4h 00mnonstop
Southwest Logo
9:40 pm - 12:10 am
MDW
-
SEA
4h 30mnonstop
$355Southwest
Wed, May 27 - Wed, Jun 3
Southwest Logo
6:00 am - 12:00 pm
SEA
-
MDW
4h 00mnonstop
Southwest Logo
9:40 pm - 12:10 am
MDW
-
SEA
4h 30mnonstop
$356Southwest
Thu, Oct 15 - Tue, Oct 20
Delta Logo
9:20 pm - 9:25 am
SEA
-
EVV
10h 05m
1 stop
Delta Logo
5:45 pm - 12:09 am
EVV
-
SEA
8h 24m
1 stop
$496Delta
Wed, Jun 10 - Wed, Jun 17
Delta Logo
11:59 pm - 9:28 am
SEA
-
EVV
7h 29m
1 stop
Delta Logo
10:08 am - 8:50 pm
EVV
-
SEA
12h 42m
2 stops
$851Delta
Booking Insights

KAYAK's insights & trends for Seattle to Illinois flights

Get data-powered insights and trends into flights from Seattle to Illinois to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from Seattle to Illinois?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Seattle to Illinois departing in May.

What is the cheapest Seattle to Illinois flight route?

Data is based on round-trip flight searches on KAYAK over the past month.

The cheapest ticket to Illinois from Seattle found in the last 72 hours was to Chicago, at $248 round-trip. The most popular route is from Seattle (SEA) to Chicago O'Hare Intl Airport (ORD), and the cheapest round-trip airline ticket found on this route in the last 72 hours was $256.

What is the cheapest time of day to fly to Illinois?

The average price for all round-trip flights from Seattle to Illinois depending on the time of departure, clicked by users on KAYAK in the last 2 weeks.

The cheapest time of day to fly to Illinois is generally in the evening, when round-trip flights cost $312 on average. Morning departures are around 42% more expensive than evening flights, on average. The most expensive time of day to fly to Illinois is generally in the morning, which is peak travel time and where the average cost of a ticket is $442.

Can I save money by flying with a layover from Seattle to Illinois?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

No, with an average price for the route of $383, prices are generally cheapest when you fly direct.

What is the cheapest month to fly from Seattle to Illinois?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Seattle to Illinois, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Seattle to Illinois is January, when tickets cost $47 (return) on average. On the other hand, the most expensive months are March and December, when the average cost of round-trip tickets is $665 and $503 respectively.

What’s the cheapest day of the week to fly from Seattle to Illinois?

The average price of all round-trip flights from Seattle to Illinois clicked on KAYAK for each day over the last 12 months.

For Seattle to Illinois, Wednesday is the cheapest day to fly on average and Monday is the most expensive. Flying from Illinois back to Seattle, the best deals are generally found on Friday, with Monday being the most expensive.

How far in advance should I book a flight from Seattle to Illinois?

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Seattle to Illinois, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Seattle to Illinois, you should book around 4 weeks before departure, which saves you about 46% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 10 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$82
Best time to beat the crowds with an average 12% drop in price.
Most popular time to fly with an average 7% increase in price.
Flight from Seattle to St. Louis

FAQs - booking Illinois flights

  • How does KAYAK find such low prices on flights from Seattle to Illinois?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Seattle to Illinois.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Seattle to Illinois?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Seattle to Illinois is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Seattle to Illinois?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from Seattle to Illinois with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Seattle to Illinois?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Seattle to Illinois up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top tips for finding cheap flights to Illinois

  • Looking for a cheap flight? 25% of our users found tickets from Seattle to the following destinations at these prices or less: Chicago $184 one-way - $363 round-trip

Reviews of the top 5 airlines serving from Seattle to Illinois

 
See real verified KAYAK customer reviews for airlines flying from Seattle to Illinois. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Seattle to Illinois? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4314 reviews
8.6Crew
8.1Boarding
7.5Entertainment
8.0Comfort
7.0Food
Airline reviews

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

10.0 Excellentlarry, Apr 2026
LGB - PHX
Read more Southwest reviews

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

no service at all due to turbulence. they should've at least given us snacks, there were only 10 people on the entire flight.

First time I've had to use the disabled accommodations. And I could not have had a better experience with Southwest, i was having trouble getting from one terminal to another due to my heart failure. And the next thing I know a Southwest agent had made sure. I had a wheelchair at all my flights. Can't thank them enough.

Delayed flight, lack of information, boarding process is a mess as is the carryon luggage causing issues when leaving the plane….just a poor experience.

Comfortable. Easy. No problems. Just wish they had gf options for snacks.

The crew was very kind and made going to Hawaii relaxing and fun to look forward to! Thank you Southwest for a pleasant flight!

This leg was much better, but we did have to have a 3 hour lay o er after coming from a very exhausting hiccup with our flight from BNA to Den

We waited in the airplane for over 45 min for a southwest employee to make the flight. This cause over half the plane to miss their connecting flight in Denver. When we confronted the desk upon arrival, they told us the only flight they had was the next day leaving at 8:50 pm!!! Or they offered to get us to Burbank or LA, but after that we were on our own to get back to Santa Barbara. I paid for a flight from sba to bna bna to sba. My re entry into mom mode has been 💯 rough because of southwest mistake with my flight. And now I’m leaving to Reno tomorrow for a vballl tournament and just discovered that my leg in Vegas has me and my 3 kids on a stand by flight even though I had booked these ticket last year November!! Do better southwest!

Southwest is kind of a slum airline. It’s gotten more expensive over the years for less and less service. I am a Southwest Chase Visa card holder and was forced to choose a seat in the 26th row in the middle seat. However my wife who is a rewards member but doesn’t hold a card or anything else, gets randomly assigned a normally paid seat in row 6! How does that work?

For the first time in a long time, the Wi-Fi actually worked the entire flight! The flight crew was amazing as usual.

The crew was great and everything went smoothly coming and going.

My window seat did not have a window. I chose seat 11A thinking I would have a view. I had a wall instead.

See what I wrote in the previous section. This was a terrible experience. I would like refund.. I even paid an extra $70 for an aisle seat closer to the front to ensure that I got off early enough to catch the next flight. The fact that the plane did not wait, and even left eearlier, knowing that the first flight came in late, and was moved to a terminal three train stops away is appalling. My friend that flew JetBlue, their flight was delayed and came in later and the connecting flight WAITED for them. How is it that JetBlue could do that, and Alaska could not.

This was my second time flying Alaska Airline in the 1st Class cabin. Everything was fine with the exception of the food and entertainment. The food was just ok but not what I was expecting from 1st Class. A BBQ pork sandwich and baked potato. There wasnt any in-flight entertainment. I found that odd since it was a coast to coast flight Seattle to Dulles. My sister flew 1st Class on Delta on a shorter flight ( Seattle to Cincinnati) and had an awesome meal and in-flight entertainment. I typically fly Delta but there wasn’t a flight with times that fit my schedule. I am by no means a primary donna. But when my upgrade cost over $900…I didn’t use any reward miles…I was expecting more than what I got. I will never fly Alaska Airline 1st Class again. I will stick with Delta for all my travel needs whether it’s in 1st Class or coach.

Good staff. Comfortable seats. Had to check my bag because the flight was too full.

Loved this first class flight! Awesome food, snacks and drinks. Comfortable seat with foot rest. Good movie. Very friendly crew! Only thing I would suggest is having a screen on seat back in front of me so I didn’t have to watch the movie on my phone.

The crew was very attentive, boarding was orderly. I really liked the way Alaska Airlines gives boarding passes and dropping off my bags. Very smooth.

Once we were in the air, the flight was nice and smooth. The flight was about twenty minutes late to begin with, though, and then we needed to wait to land for another plane to land first.

Flight crew great! No WiFi not great. Someone took my bag not great!

Alaska Airlines staff go out of their way to accommodate my fragile musical instrument, every time. They are unlike any other airline. I've experienced this can-do attitude on several flights with different staff, so this must be the culture of their company. I appreciate Alaska!

The agent at check in and at the gate were less than thrilled to be at work. I'm not a fan of Kayak's placement on the plane. I got put in the middle seat and none of my preferences were used.

In ATL they have two sets of departure screens. Follow what is on your airline's departure board - the ATL Airport Authority departure board had completely incorrect details about the gate assignment for my flight, which would have made me miss boarding.

Crew was nice, meal was good. Entertainment had to be rebooted 3 times and still did not work. Turns out there was residue on screen, it needed to be cleaned to prevent the touchscreen buttons from continuously activating. I had entertainment for the last 45 minutes of a 5 hour 45 minute flight. Really unacceptable for first class. Flight attendent indicated your cleaning solution creates this problem. Seems as if this is widely known, you should be using a different product or cleaning better. Really really disappointing which simply added to the wi fi on your planes with reliably never ever works.

Snacks and included beverages were appreciated. Boarding went smoothly. Plenty of overhead bin space. Seats get very uncomfortable after a couple of hours. After waiting 10 painful minutes for my walker, a very nice Delta guest agent pushed me in a wheelchair to the gate. It was finally delivered to me after another 15 minutes . Our checked bag was on the carousel long b4 I was able to retrieve it. Fortunately it was still there but somewhere along the way the straps we used to secure it were removed and and were not reattached. Wish I had made note of the agents name.

It was fine. 55 minute flight. No snacks or beverage service offered. Boarding went smoothly and my walker was waiting for me on the jet way.

The cabin temperature was nice and cool. The wifi was not working.

Could not get my connecting flight boarding pass until four hrs before departure! Ver annoying especially since the staff could not explain why!

There was an unruly family behind us that made the short flight miserable!!! The cabin crew did nothing to contain it.

First flight out and was 85 minutes delayed. Notification came out way too late

Flight delay was frustrating, also you cannot checkin online without delta app, web browser check-in throw errors

Standard flight with a drinks and a snack- overall very quick flight. The flight attendants were very strict, bordered on rude.

Delayed - weather wasn't bad at either end. Also sat on tarmac in ORD.

boarded early to only find out that flight would sit at gate for 45 min to an hour. Landed in chicago and sat on runway for over an hour before got to gate. Total delay was extensive for a 45 min flight door to door.

The flight was significantly delayed. The inbound flight from EWR was delayed departing because of mechanical problems. My original departure from CLT was 5:28 pm but due to the delay of the inbound flight, after arrival, deplaning, cleaning, boarding, we did not push back from the gate until 9:00 pm. Once in the air, the flight was smooth and what was originally supposed to be an arrival in ORD at 7:30 pm local time turned out to be 9:35 pm.

The flight I was supposed to be on was supposed to take off at 1:50 from State College. It was delayed over and over and over again until somehow I had to rebook on a flight that was supposed to have left State College at 8 am that morning but didn't end up taking off until almost 6 pm. Not only was this completely unacceptable, the "token from United" was a 15 dollar meal voucher that has to be used by today. I would personally like some miles added to my account for this inconvenience. I was in transit for 8 hours from the time I arrive at State College Aiport to when I got home. I was supposed to be home at 3 pm and I returned at 8 pm. Unacceptable. I have not been on an on Time united flight in nearly 5 years.

newer aircraft, ability to connect my headset via blue tooth for entertainment.

Very comfortable flight, snacks and drinks were good, good communication from crew. Could have used a little more information on timing of boarding for group 5

Great flight. Got to watch a movie. Smooth flight and early arrival at ORD.

It was better than excellent. The staff in Mason City were great. The young woman that pushed my wheelchair did more than could be expected of her. She came from India 17 years ago. I don't remember her name.

After arriving in Chicago, we were taxiing for 1.5 hours with infrequent and untruthful updates about the amount of time it would take to arrive at the gate. Minimally, the team could have provided timing expectations that were more truthful, especially one their original expectations were not met.

It was good, the staff was great, and the food, was as usual, tea and biscuit. Bathroom was clean, and the plane was clean as well.

Very good I can’t complain one bit. Thank you American Airlines for making my flight enjoyable and safe!

The staff and service on American Airlines were truly outstanding. I had requested wheelchair assistance for my mother due to her knee issues, and the team went above and beyond every step of the way—from boarding in Boston to our arrival in Chicago. Their care, professionalism, and attentiveness made the entire experience smooth and stress-free. I’m very grateful for the support they provided.

The new planes (American Eagle) are beautiful and especially comfortable. The flight attendants are consistently professional and courteous. And, while it may seem inconsequential, the new liquid tube of coffee creamer—in contrast to the powdered coffee creamer—makes all the difference in a cup of coffee.

Boarding was quick and efficient. We arrived at our destination early.

I'm not sure American is capable of on-time arrivals and departures. When you land at ORD, you almost always get held on the tarmac because your gate is still occupied. I may have missed my connection, but that ended up up being significantly delayed as well. Once again, I finally got home well after midnight.

We did not have enough time to make our connecting flight. As a result, we were put onto a different airline for our second leg. The different airline was NOT comparable to British Airlines, and our arrival was significantly delayed. The actual flight on BA was amazing.

Crew at the gate was very crabby and not at all polite. The plane was very hot the entire flight. And the seat cushion was very worn out.

The staff are very, very professional. It's what flying should feel like.

Flight was delayed half hour before boarding, but when I checked flight aware the plane that would Pick us up had a delay of more than an hour. AA should let us know in advance to avoid waiting several hours in the airport

Everything you need to know for your flight from Seattle to Illinois

Information on your arrival and departure airports