$70 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 4/24. 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$192
Moline
Moline1 stop$329
Peoria
Peoria1 stop$320
Bloomington
Bloomington1 stop$349
Champaign
Champaign1 stop$290
Springfield
Springfield1 stop$515
St. Louis
St. Louisnonstop$217
Decatur
Decatur1 stop$398
Paducah
Paducah1 stop$383
Chicago
Chicago1 stop$192
Moline
Moline1 stop$329
Peoria
Peoria1 stop$320
Bloomington
Bloomington1 stop$349
Champaign
Champaign1 stop$290
Springfield
Springfield1 stop$515
St. Louis
St. Louisnonstop$217
Decatur
Decatur1 stop$398
Paducah
Paducah1 stop$383

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

Fri, Apr 24 - Tue, Apr 28
Frontier Logo
11:07 am - 5:50 am
SEA
-
ORD
16h 43m
1 stop
Frontier Logo
7:21 pm - 5:42 pm
ORD
-
SEA
24h 21m
1 stop
$192Frontier
Wed, Apr 15 - Tue, Apr 21
Multiple Airlines Logo
8:07 pm - 9:50 am
SEA
-
ORD
11h 43m
1 stop
Multiple Airlines Logo
7:30 am - 5:42 pm
ORD
-
SEA
12h 12m
1 stop
$194Multiple Airlines
Thu, Apr 9 - Wed, Apr 15
Delta Logo
5:55 pm - 11:52 pm
SEA
-
ORD
3h 57mnonstop
Delta Logo
6:00 pm - 8:43 pm
ORD
-
SEA
4h 43mnonstop
$197Delta
Thu, Apr 23 - Tue, Apr 28
Southwest Logo
11:55 pm - 5:55 am
SEA
-
MDW
4h 00mnonstop
Southwest Logo
10:15 am - 12:45 pm
MDW
-
SEA
4h 30mnonstop
$197Southwest
Fri, Apr 17 - Sun, Apr 26
American Airlines Logo
1:19 pm - 7:49 pm
SEA
-
ORD
4h 30mnonstop
American Airlines Logo
10:00 pm - 12:36 am
ORD
-
SEA
4h 36mnonstop
$198American Airlines
Fri, Apr 17 - Wed, Apr 22
United Airlines Logo
3:48 pm - 12:30 am
SEA
-
ORD
6h 42m
1 stop
United Airlines Logo
8:00 pm - 10:42 pm
ORD
-
SEA
4h 42mnonstop
$199United Airlines
Thu, Apr 30 - Tue, May 5
American Airlines Logo
3:17 pm - 9:40 pm
SEA
-
ORD
4h 23mnonstop
American Airlines Logo
7:30 am - 10:14 am
ORD
-
SEA
4h 44mnonstop
$200American Airlines
Sat, Apr 25 - Wed, Apr 29
Alaska Airlines Logo
5:57 pm - 11:59 pm
SEA
-
STL
4h 02mnonstop
Alaska Airlines Logo
7:00 am - 9:32 am
STL
-
SEA
4h 32mnonstop
$217Alaska Airlines
Wed, Apr 8 - Wed, Apr 22
Alaska Airlines Logo
6:02 pm - 11:59 pm
SEA
-
STL
3h 57mnonstop
Alaska Airlines Logo
7:00 am - 9:32 am
STL
-
SEA
4h 32mnonstop
$227Alaska Airlines
Tue, Apr 28 - Fri, May 29
United Airlines Logo
11:59 pm - 10:02 am
SEA
-
PIA
8h 03m
1 stop
United Airlines Logo
5:33 pm - 11:59 pm
PIA
-
SEA
8h 26m
1 stop
$320United Airlines
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.

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 $206 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 $206.

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 $291 on average. Morning departures are around 50% 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 $437.

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 $307, 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 February, when tickets cost $217 (return) on average. On the other hand, the most expensive months are December and March, when the average cost of round-trip tickets is $367 and $338 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 Sunday is the most expensive. Flying from Illinois back to Seattle, the best deals are generally found on Wednesday, 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 50% 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$70
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 $180 one-way - $320 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
Alaska AirlinesOverall score based on 12042 reviews
8.1Boarding
8.5Crew
7.0Entertainment
7.1Food
7.8Comfort
Airline reviews

The crew inside the airport for Alaska was rude, lazy and incompetent

10.0 ExcellentAnonymous, Mar 2026
SEA - BZN
Read more Alaska Airlines reviews

The crew inside the airport for Alaska was rude, lazy and incompetent

The flight was extremely smooth, and so was the landing. Great piloting.

Plane was clean, staff was professional and flight was on time. No built in tv was still ok, as programs were offered that could synch to smart phones.

J was in the ER x 3...3 protruding discs...contacted Alaska many many days prior to cancel and request a refund or a credjt.. they only gave me 50 % credit....outrageous seeing how i have a doctors letter....just plain inhuman. AI sucks!

The flight was too short. No snacks or drinks offered.

The flight attendant was friendly and attentive. Although our interaction was brief—- it made a difference. The crew was upfront about turbulence. I like the Maui pretzels.

Everything was good. Please have a wheat free option for snacks in the future.

They are always so great! Friendly, on time if not early, organized boarding process. Great price too.

Crew very courteous. Boarding was great. Slow to get baggage at Denver.

Lester and the rest of the crew were such a joy. Also, I want to thank the pilots for getting us there on time, and safely. My first amd only choice will always be Alaska Airlines.

We landed and sat on the tarmac for 45 minutes because they only have one gate at the airport and there was another plane running late so we had to wait

The WiFi was not working. That made for a long flight.

Absolutely no communication on why there's a delay and multiple flight time reschedules. I would have canceled the flight and drove back home if I known it was going to be rescheduled 3 or 4 times.

Another late night flight and MORE men belligerently drinking and yelling. I had to move from first to economy because they were so obnoxious and disruptive. Crazy to go from a cozy chair to cardboard when you were supposed to be in first. Delta allows was too much drinking which leads to belligerent behavior.

I was in first class and literally the men behind me were so aggressively loud I moved myself to economy. This has become so common on Delta - people using audio without headphones, and men on 12am / late night flights drinking and yelling to talk to each other which prevents anyone around them from resting. Pretty crazy to have to move from first to economy (poorer service, less comfort...). Wild wild. Looking into other airlines.

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

Was forced to check in my small carry on, even though I informed the crew it has very fragile items inside

The crew were exceptionally nice and accommodating. My wife was tired after the flight from Haneda, Tokyo. They let her sleep and served her dinner later after she woke up, before we landed in PDX.

No charging outlets worked. Other than collecting trash attendants didn’t come around. No one could hear flight attendants announcements during the flight. Seat pads were horrible. Sitting on a board for 5 hours. What happened to Hawaiian airlines comfort, hospitality, and extras? Our pilots did an excellent job trying to minimize turbulence and incredible job in landing in windy conditions.

There was no wifi available at any price -- the plane did not have wifi equipment. Movie choices were blah - hits from the past; nothing recent. The food was blah airplane food. They should have had Mai Tai drinks available as per the Hawaiian Airlines magazine, but they had none onboard.

I like that if they asked you to checked in a bag at the gate they give you priority to board

Horrible food and crew. Crew were laughing and talking loud while people were trying to sleep

Yall need to integrate your system with Alaska more efficiently. They booted me off the first flight because of a discrepancy on your end.

The crew at Hawaiian Airlines was fantastic. Kind and hard working. The pilots were great with giving us all the updates to make sure we were informed.

Very good. Nice plane and we sat in economy plus - bigger seats, more room. They served a meal and snacks, and the meal was an apple stuffed pancake that was very good! The snack for us was a hummus sandwich - also very good. The flight attendants were helpful and nice. They have plenty of movies and shows to watch. My only negative -- they changed our flights around and did not adjust the layovers, so we ended up with a very long and unnecessary layover in Honolulu.

I liked the Starlink WiFi but didn't like how they said they were the only airline to offer a free meal and it turns out to be just a standalone sandwich and then charge for snacks to go with it. Rather have the free snacks like Southwest, but have the option to purchase a decent meal for a 5+ hour flight.

Flight scheduled to take off at 5.55pm but it did not take off until 7pm due to some food delivery delay.

Wonderful. Quick boarding. Early departure and we arrived 30 minutes early at our destination. Unfortunately, when you arrive early, there is still a departing aircraft at our gate. We had to park for 30 minutes until the gate was clear. So our early arrival was not really early at the gate. Otherwise it was a quick and smooth flight. Appreciated the efficiency.

Crew was great (professional, attentive, prompt). Snacks for 4 hrs flight is deplorable.

United Airlines is my preferred airlines and I am thankful for Gary who also help support me on the phone to switch my flight literally last min.

Seated dude next to me even though lots of empty rows. But main thing was we sat on the tarmac after landing for 30 minutes because of, in the words of the dude who sat next to me, “operational incompetence”. We got changing directions about where to pick up gate checked bags. Pilot and flight attendant were awesome though.

It was a pretty standard flight... until the almost hour and a half spent on the taxi way. I get that the weather has been poor but the delay had nothing to do with the weather and more to do with a plane with several issues tying up the gate. I get that that happens from time to time but this has been EVERY flight I've been on for the past 5 years and I fly 3 to 5 times a year. This isn't just United... it's American, it's Delta. It's an issue with the entire industry. I work for UPS and packages on a cargo plane get better service than people do these days. Anymore I HATE flying.

Perfect flight. Smooth flight. Arrived 20 minutes early at destination. Excellent service.

The flights were on time which was great give. It was holiday travel season and there’d been some weather issues. The only complaint and this is every time with United is the terrible seat design. The head rest is not built for comfort and having my neck bent forward for a cross country trip reminded me while I try not to take United flights as a rule.

Everything was absolutely wonderful from check in to baggage claim. Staff was very professional and sweet. Will definitely recommend United to family and friends.

They did the one thing that really matters - got to Chicago early.

The flight was on time. I generally don’t drink or eat on short flights and the seats were good and the flight attendants were friendly. That’s all I expect

There was no inflight service. Once we landed we were delayed to find a gate for an hour and a half which was 1/2 the total time in the air.

The chicken wrap was tiny ($13 for what looked like a 1/3 of a normal wrap?) and disgusting.

It was good experience this time. The flight was on time.

There was a delay with the plan which cause the flight to leave later and once arrived in Chicago there was another delay and some passengers missed their connecting flights

The gate agent had a really bad attitude and refused to help me get on the standby list. She just handed me a card and said I needed to call a number. I asked her to help with the AA app on my phone and she just shrugged and said she didnt know. After a few phone calls, I eventually just went to a different gate agent on the other side of the terminal and got the help I needed.

Overall, my last three trips on American Airlines have all been either delayed or "rescheduled" due to mechanical issues. At least on delay caused me to miss two possible connecting flights each later than the first. My last option for my last connection required the assistance of the onsite service desk (O'Hare Airport). The wait time for the service desk was such that it jeopardized getting booked on the last connecting flight available for the night. Suffice it to say, my latest experiences with American Airlines have caused me extensive loss of productive business and personal time and can therefore be classified as significantly less than satisfactory.

Waiting for gate in RDU for more than 20mins is crazy.

American Airlines was great and worked very hard to change my ticket so I could get an earlier, direct flight back to Dallas. However, I was informed that Kayak made mistakes with my itinerary and classified my ticket as desiring to be on the earlier flight instead of taking the necessary step of calling AA to get me on the standby list. This ended up keeping me from being added to the standby list and delayed me getting home by 6 hours. I am happy to discuss this further with Kayak so they can correct their procedures so this won't happen again.

Waited for oxygen tanks for 30 minutes after boarding was complete.

We flew in first class. The crew did not offer drinks before the flight took off, but they treated us well during the flight. The food was excellent. There was actually too much food served, but it was nice to have all the options.

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

Information on your arrival and departure airports