$158+ 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 8/29. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Aug 2 — Aug 91
Round-trip
1 adult, Economy
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Find cheap flights from Seattle to Illinois with Cheapflights
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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 July 3, 2026.
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 July 3, 2026.
This American Airlines deal was found by Cheapflights users on 7/3. 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 10/176:12 am
SEA
- PIA
1 stop8h 47m
American Airlines
Sat 10/244:43 pm
PIA
- SEA
1 stop9h 27m
American Airlines
Deal found 7/3![American Airlines logo]()
$271
This Priceline deal was found by Cheapflights users on 7/1. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/2312:14 am
SEA
- ORD
Nonstop4h 06m
Multiple Airlines
Mon 10/266:50 am
ORD
- SEA
1 stop12h 55m
Multiple Airlines
Deal found 7/1![Multiple Airlines logo]()
$341
This Kiwi.com deal was found by Cheapflights users on 6/29. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/225:51 pm
SEA
- ORD
Nonstop4h 08m
Multiple Airlines
Wed 8/262:41 pm
ORD
- SEA
1 stop20h 38m
Multiple Airlines
Deal found 6/29![Multiple Airlines logo]()
$342
This Gotogate deal was found by Cheapflights users on 6/28. 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.
Wed 7/225:48 pm
SEA
- ORD
Nonstop4h 11m
Multiple Airlines
Sun 7/269:57 pm
ORD
- SEA
1 stop13h 20m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$343
This American Airlines deal was found by Cheapflights users on 7/3. 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 10/175:00 am
SEA
- BMI
1 stop8h 28m
American Airlines
Sat 10/243:58 pm
BMI
- SEA
1 stop10h 12m
American Airlines
Deal found 7/3![American Airlines logo]()
$343
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Wed 7/88:13 pm
SEA
- ORD
1 stop7h 24m
Multiple Airlines
Fri 7/248:20 pm
ORD
- SEA
Nonstop4h 44m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$344
This CheapOair deal was found by Cheapflights users on 7/1. 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.
Thu 7/167:06 pm
SEA
- ORD
1 stop23h 46m
Frontier
Wed 7/229:57 pm
ORD
- SEA
1 stop13h 20m
Frontier
Deal found 7/1![Frontier logo]()
$345
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Mon 7/1310:34 am
SEA
- ORD
1 stop17h 43m
Multiple Airlines
Wed 7/226:00 am
ORD
- SEA
Nonstop4h 38m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$346
This American Airlines deal was found by Cheapflights users on 6/28. 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.
Thu 8/135:00 am
SEA
- BMI
1 stop9h 19m
American Airlines
Sat 8/155:40 pm
BMI
- SEA
1 stop8h 33m
American Airlines
Deal found 6/28![American Airlines logo]()
$346
This Kiwi.com deal was found by Cheapflights users on 7/1. 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.
Wed 7/88:13 pm
SEA
- ORD
1 stop7h 24m
Multiple Airlines
Mon 7/206:00 am
ORD
- SEA
Nonstop4h 38m
Multiple Airlines
Deal found 7/1![Multiple Airlines logo]()
$347
This Expedia deal was found by Cheapflights users on 6/28. 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.
Wed 7/88:13 pm
SEA
- ORD
1 stop7h 24m
Multiple Airlines
Tue 7/145:42 pm
ORD
- SEA
Nonstop4h 39m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$348
This Kiwi.com deal was found by Cheapflights users on 6/30. 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 7/910:34 am
SEA
- ORD
1 stop17h 43m
Multiple Airlines
Fri 7/246:42 pm
ORD
- SEA
Nonstop4h 52m
Multiple Airlines
Deal found 6/30![Multiple Airlines logo]()
$349
Best flights from Seattle to IllinoisDiscover carefully curated flight deals from Seattle to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 3, 2026.
Discover carefully curated flight deals from Seattle to Illinois that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 3, 2026.
This American Airlines deal was found by Cheapflights users on 6/28. 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.
Thu 9/245:30 am
SEA
- BMI
1 stop8h 24m
American Airlines
Sun 9/275:02 am
BMI
- SEA
1 stop7h 07m
American Airlines
Deal found 6/28![American Airlines logo]()
$349
This Delta deal was found by Cheapflights users on 7/1. 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 10/3111:59 pm
SEA
- MLI
1 stop9h 22m
Delta
Thu 11/55:10 pm
MLI
- SEA
1 stop8h 42m
Delta
Deal found 7/1![Delta logo]()
$349
This United Airlines deal was found by Cheapflights users on 6/28. 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.
Tue 9/15:13 pm
SEA
- ORD
Nonstop4h 04m
United Airlines
Sat 9/54:20 pm
ORD
- SEA
Nonstop4h 47m
United Airlines
Deal found 6/28![United Airlines logo]()
$357
This Southwest deal was found by Cheapflights users on 6/30. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/286:35 am
SEA
- MDW
Nonstop3h 55m
Southwest
Sat 11/72:05 pm
MDW
- SEA
Nonstop4h 40m
Southwest
Deal found 6/30![Southwest logo]()
$357
This Alaska Airlines deal was found by Cheapflights users on 6/30. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/111:10 pm
SEA
- ORD
Nonstop4h 11m
Alaska Airlines
Mon 8/176:42 pm
ORD
- SEA
Nonstop4h 52m
Alaska Airlines
Deal found 6/30![Alaska Airlines logo]()
$360
This Kiwi.com deal was found by Cheapflights users on 6/29. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/177:41 pm
SEA
- RFD
2 stops20h 30m
Multiple Airlines
Sun 9/209:29 pm
RFD
- SEA
1 stop14h 31m
Multiple Airlines
Deal found 6/29![Multiple Airlines logo]()
$375
This Delta deal was found by Cheapflights users on 6/30. 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.
Thu 8/2710:35 pm
SEA
- MLI
1 stop9h 50m
Delta
Sun 8/306:00 am
MLI
- SEA
1 stop9h 40m
Delta
Deal found 6/30![Delta logo]()
$349
This American Airlines deal was found by Cheapflights users on 6/30. 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.
Fri 8/283:35 pm
SEA
- PIA
1 stop6h 24m
American Airlines
Sun 8/304:43 pm
PIA
- SEA
1 stop10h 07m
American Airlines
Deal found 6/30![American Airlines logo]()
$349
This United Airlines deal was found by Cheapflights users on 6/30. 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.
Wed 10/2811:03 pm
SEA
- ORD
Nonstop4h 08m
United Airlines
Sat 11/79:00 am
ORD
- SEA
Nonstop4h 53m
United Airlines
Deal found 6/30![United Airlines logo]()
$357
This Southwest deal was found by Cheapflights users on 6/28. 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.
Sat 8/225:30 am
SEA
- MDW
1 stop6h 40m
Southwest
Sat 8/296:25 pm
MDW
- SEA
Nonstop4h 30m
Southwest
Deal found 6/28![Southwest logo]()
$363
This Alaska Airlines deal was found by Cheapflights users on 7/2. 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.
Wed 9/212:16 am
SEA
- ORD
Nonstop4h 04m
Alaska Airlines
Fri 9/111:03 pm
ORD
- SEA
Nonstop4h 38m
Alaska Airlines
Deal found 7/2![Alaska Airlines logo]()
$371
This Delta deal was found by Cheapflights users on 6/30. 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.
Fri 9/2511:59 pm
SEA
- MLI
1 stop8h 24m
Delta
Mon 9/285:16 pm
MLI
- SEA
1 stop8h 43m
Delta
Deal found 6/30![Delta logo]()
$349
This United Airlines deal was found by Cheapflights users on 6/29. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/211:57 pm
SEA
- ORD
Nonstop4h 21m
United Airlines
Sat 9/268:12 pm
ORD
- SEA
Nonstop4h 44m
United Airlines
Deal found 6/29![United Airlines logo]()
$360
This Southwest deal was found by Cheapflights users on 6/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/315:15 am
SEA
- MDW
Nonstop4h 00m
Southwest
Wed 9/211:00 am
MDW
- SEA
1 stop8h 30m
Southwest
Deal found 6/29![Southwest logo]()
$370
This Alaska Airlines deal was found by Cheapflights users on 6/30. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/36:00 am
SEA
- ORD
Nonstop4h 07m
Alaska Airlines
Mon 9/76:00 am
ORD
- SEA
Nonstop4h 30m
Alaska Airlines
Deal found 6/30![Alaska Airlines logo]()
$371
This Delta deal was found by Cheapflights users on 7/2. 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 8/187:15 am
SEA
- ORD
Nonstop4h 08m
Delta
Sat 8/227:00 am
ORD
- SEA
Nonstop4h 37m
Delta
Deal found 7/2![Delta logo]()
$357
This Expedia deal was found by Cheapflights users on 7/2. 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.
Fri 8/71:10 pm
SEA
- ORD
Nonstop4h 11m
Alaska Airlines
Mon 8/108:20 pm
ORD
- SEA
Nonstop4h 44m
Alaska Airlines
Deal found 7/2![Alaska Airlines logo]()
$371
This United Airlines deal was found by Cheapflights users on 7/3. 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 10/171:56 pm
SEA
- PIA
1 stop7h 02m
United Airlines
Sat 10/2410:43 am
PIA
- SEA
2 stops11h 54m
United Airlines
Deal found 7/3![United Airlines logo]()
$374
This Southwest deal was found by Cheapflights users on 7/2. 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.
Fri 10/25:00 am
SEA
- MDW
Nonstop3h 55m
Southwest
Sun 10/410:20 pm
MDW
- SEA
Nonstop4h 30m
Southwest
Deal found 7/2![Southwest logo]()
$379
This Kiwi.com deal was found by Cheapflights users on 7/2. 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.
Wed 8/58:13 pm
SEA
- RFD
1 stop14h 21m
Multiple Airlines
Sun 8/91:24 pm
RFD
- SEA
2 stops21h 40m
Multiple Airlines
Deal found 7/2![Multiple Airlines logo]()
$465
This Alaska Airlines deal was found by Cheapflights users on 6/28. 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 8/187:26 am
SEA
- ORD
1 stop9h 31m
Alaska Airlines
Wed 8/196:01 am
ORD
- SEA
1 stop8h 38m
Alaska Airlines
Deal found 6/28![Alaska Airlines logo]()
$377
This United Airlines deal was found by Cheapflights users on 7/2. 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 9/1111:00 pm
SEA
- ORD
Nonstop4h 06m
United Airlines
Sun 9/138:01 pm
ORD
- SEA
Nonstop4h 44m
United Airlines
Deal found 7/2![United Airlines logo]()
$379
This Delta deal was found by Cheapflights users on 6/29. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/95:53 pm
SEA
- ORD
Nonstop4h 04m
Delta
Tue 10/136:55 am
ORD
- SEA
Nonstop4h 42m
Delta
Deal found 6/29![Delta logo]()
$382
This Southwest deal was found by Cheapflights users on 6/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/15:20 am
SEA
- MDW
Nonstop3h 55m
Southwest
Sun 9/64:55 pm
MDW
- SEA
Nonstop4h 30m
Southwest
Deal found 6/29![Southwest logo]()
$382
This American Airlines deal was found by Cheapflights users on 7/2. 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.
Wed 8/191:24 pm
SEA
- EVV
1 stop8h 35m
American Airlines
Mon 8/2412:20 pm
EVV
- SEA
1 stop8h 27m
American Airlines
Deal found 7/2![American Airlines logo]()
$486
This Alaska Airlines deal was found by Cheapflights users on 6/29. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/37:01 am
SEA
- ORD
1 stop9h 52m
Alaska Airlines
Tue 10/67:20 am
ORD
- SEA
1 stop9h 57m
Alaska Airlines
Deal found 6/29![Alaska Airlines logo]()
$377
This Southwest deal was found by Cheapflights users on 7/1. 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 10/156:15 am
SEA
- MDW
2 stops9h 30m
Southwest
Wed 10/216:05 am
MDW
- SEA
1 stop6h 45m
Southwest
Deal found 7/1![Southwest logo]()
$385
This United Airlines deal was found by Cheapflights users on 7/2. 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.
Wed 9/3011:13 pm
SEA
- PIA
1 stop8h 53m
United Airlines
Sat 10/34:05 pm
PIA
- SEA
1 stop8h 51m
United Airlines
Deal found 7/2![United Airlines logo]()
$410
This Southwest deal was found by Cheapflights users on 6/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/56:25 pm
SEA
- MDW
1 stop9h 30m
Southwest
Mon 9/77:30 am
MDW
- SEA
1 stop9h 30m
Southwest
Deal found 6/29![Southwest logo]()
$388
This Delta deal was found by Cheapflights users on 6/29. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/265:30 am
SEA
- MLI
2 stops14h 49m
Delta
Sat 8/2911:08 am
MLI
- SEA
1 stop9h 57m
Delta
Deal found 6/29![Delta logo]()
$467
Last-minute flights from Seattle to IllinoisDiscover last-minute flight deals from Seattle to Illinois. Data last updated July 3, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Illinois. Data last updated July 3, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Wed 7/88:13 pm
SEA
- ORD
1 stop7h 24m
Multiple Airlines
Fri 7/248:20 pm
ORD
- SEA
Nonstop4h 44m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$344
This Kiwi.com deal was found by Cheapflights users on 7/1. 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.
Wed 7/88:13 pm
SEA
- ORD
1 stop7h 24m
Multiple Airlines
Tue 7/218:20 pm
ORD
- SEA
Nonstop4h 44m
Multiple Airlines
Deal found 7/1![Multiple Airlines logo]()
$347
This Expedia deal was found by Cheapflights users on 6/28. 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.
Wed 7/88:13 pm
SEA
- ORD
1 stop7h 24m
Multiple Airlines
Tue 7/145:42 pm
ORD
- SEA
Nonstop4h 39m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$348
This Kiwi.com deal was found by Cheapflights users on 7/1. 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 7/910:34 am
SEA
- ORD
1 stop17h 43m
Multiple Airlines
Fri 7/248:20 pm
ORD
- SEA
Nonstop4h 44m
Multiple Airlines
Deal found 7/1![Multiple Airlines logo]()
$349
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Mon 7/1310:34 am
SEA
- ORD
1 stop17h 43m
Multiple Airlines
Wed 7/226:00 am
ORD
- SEA
Nonstop4h 38m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$346
This CheapOair deal was found by Cheapflights users on 7/1. 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.
Thu 7/167:06 pm
SEA
- ORD
1 stop23h 46m
Frontier
Wed 7/229:57 pm
ORD
- SEA
1 stop13h 20m
Frontier
Deal found 7/1![Frontier logo]()
$345
This Gotogate deal was found by Cheapflights users on 6/28. 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.
Wed 7/225:48 pm
SEA
- ORD
Nonstop4h 11m
Multiple Airlines
Sun 7/269:57 pm
ORD
- SEA
1 stop13h 20m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$343
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Fri 7/245:48 pm
SEA
- ORD
Nonstop4h 11m
Multiple Airlines
Tue 7/289:57 pm
ORD
- SEA
1 stop13h 20m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$341
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Fri 7/245:48 pm
SEA
- ORD
Nonstop4h 11m
Multiple Airlines
Sat 7/259:57 pm
ORD
- SEA
1 stop13h 20m
Multiple Airlines
Deal found 6/28![Multiple Airlines logo]()
$342
This American Airlines deal was found by Cheapflights users on 7/1. 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.
Thu 8/135:00 am
SEA
- BMI
1 stop9h 19m
American Airlines
Sat 8/155:40 pm
BMI
- SEA
1 stop8h 33m
American Airlines
Deal found 7/1![American Airlines logo]()
$346
This Delta deal was found by Cheapflights users on 7/2. 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.
Thu 8/2711:59 pm
SEA
- MLI
1 stop8h 26m
Delta
Sun 8/305:09 pm
MLI
- SEA
1 stop8h 48m
Delta
Deal found 7/2![Delta logo]()
$349
This American Airlines deal was found by Cheapflights users on 7/1. 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.
Fri 8/283:35 pm
SEA
- PIA
1 stop6h 24m
American Airlines
Sun 8/304:43 pm
PIA
- SEA
1 stop10h 07m
American Airlines
Deal found 7/1![American Airlines logo]()
$349
One-way flights from Seattle to IllinoisSearch for one-way flight options from Seattle to Illinois. Find affordable one-way fares based on user searches. Data last updated July 3, 2026.
Search for one-way flight options from Seattle to Illinois. Find affordable one-way fares based on user searches. Data last updated July 3, 2026.
This Kiwi.com deal was found by Cheapflights users on 7/2. 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.
Sat 8/297:06 pm
SEA
- STL
2 stops20h 16m
Frontier
Deal found 7/2![Frontier logo]()
$158
This Kiwi.com deal was found by Cheapflights users on 7/2. 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.
Wed 8/58:13 pm
SEA
- STL
2 stops19h 24m
Frontier
Deal found 7/2![Frontier logo]()
$159
This Super.com deal was found by Cheapflights users on 6/29. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/198:53 pm
SEA
- STL
1 stop19h 22m
Frontier
Deal found 6/29![Frontier logo]()
$160
This Super.com deal was found by Cheapflights users on 7/1. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/278:53 pm
SEA
- STL
1 stop19h 12m
Frontier
Deal found 7/1![Frontier logo]()
$161
This Kiwi.com deal was found by Cheapflights users on 6/30. 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.
Wed 8/267:06 pm
SEA
- STL
2 stops20h 16m
Frontier
Deal found 6/30![Frontier logo]()
$162
This Frontier deal was found by Cheapflights users on 6/30. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/269:16 pm
SEA
- STL
1 stop12h 35m
Frontier
Deal found 6/30![Frontier logo]()
$163
This Kiwi.com deal was found by Cheapflights users on 7/3. 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.
Tue 9/297:00 am
SEA
- STL
2 stops24h 40m
Frontier
Deal found 7/3![Frontier logo]()
$164
This CheapOair deal was found by Cheapflights users on 7/1. 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.
Sat 8/17:06 pm
SEA
- STL
1 stop22h 17m
Frontier
Deal found 7/1![Frontier logo]()
$165
This CheapOair deal was found by Cheapflights users on 6/29. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/2912:35 pm
SEA
- STL
1 stop28h 48m
Frontier
Deal found 6/29![Frontier logo]()
$166
This Kiwi.com deal was found by Cheapflights users on 6/28. 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.
Fri 10/237:41 pm
SEA
- STL
1 stop21h 34m
Frontier
Deal found 6/28![Frontier logo]()
$167
This CheapOair deal was found by Cheapflights users on 6/28. 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.
Thu 10/159:16 pm
SEA
- STL
1 stop26h 01m
Frontier
Deal found 6/28![Frontier logo]()
$168
This American Airlines deal was found by Cheapflights users on 6/30. 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.
Fri 8/285:00 am
SEA
- CMI
1 stop7h 15m
American Airlines
Deal found 6/30![American Airlines logo]()
$169
Find flight deals from Seattle to Illinois
Keep the following information in mind while searching for Seattle to Illinois flight deals. Data was last updated July 3, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $341 (Kiwi.com) |
One-way from | $158 (Kiwi.com) |
Popular in | June |
Cheapest in | February |
Average price | $374 |
Good round-trip deal | $376 or less |
Good one-way deal | $205 or less |
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 July 3, 2026.
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
Cheapest round-trip
SeattleBloomington
SEA - BMI
SEABMI
Seattle/Tacoma Intl
Thu 9/24
5:30 am-3:54 pm
1 stop8h 24m
Bloomington-Normal
Sun 9/27
5:02 am-10:09 am
1 stop7h 07m
$349
SeattleMoline
SEA - MLI
SEAMLI
Seattle/Tacoma Intl
Sat 10/31
11:59 pm-11:21 am
1 stop9h 22m
Moline Quad-City
Thu 11/5
5:10 pm-11:52 pm
1 stop8h 42m
$349
SeattleMoline
SEA - MLI
SEAMLI
Seattle/Tacoma Intl
Thu 8/27
10:35 pm-10:25 am
1 stop9h 50m
Moline Quad-City
Sun 8/30
6:00 am-1:40 pm
1 stop9h 40m
$349
SeattlePeoria
SEA - PIA
SEAPIA
Seattle/Tacoma Intl
Fri 8/28
3:35 pm-11:59 pm
1 stop6h 24m
Greater Peoria
Sun 8/30
4:43 pm-12:50 am
1 stop10h 07m
$349
SeattleMoline
SEA - MLI
SEAMLI
Seattle/Tacoma Intl
Fri 9/25
11:59 pm-10:23 am
1 stop8h 24m
Moline Quad-City
Mon 9/28
5:16 pm-11:59 pm
1 stop8h 43m
$349
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Tue 9/1
5:13 pm-11:17 pm
Nonstop4h 04m
Chicago O'Hare Intl
Sat 9/5
4:20 pm-7:07 pm
Nonstop4h 47m
$357
SeattleChicago
SEA - MDW
SEAMDW
Seattle/Tacoma Intl
Wed 10/28
6:35 am-12:30 pm
Nonstop3h 55m
Chicago Midway
Sat 11/7
2:05 pm-4:45 pm
Nonstop4h 40m
$357
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Wed 10/28
11:03 pm-5:11 am
Nonstop4h 08m
Chicago O'Hare Intl
Sat 11/7
9:00 am-11:53 am
Nonstop4h 53m
$357
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Tue 8/18
7:15 am-1:23 pm
Nonstop4h 08m
Chicago O'Hare Intl
Sat 8/22
7:00 am-9:37 am
Nonstop4h 37m
$357
SeattleChicago
SEA - ORD
SEAORD
Seattle/Tacoma Intl
Tue 8/11
1:10 pm-7:21 pm
Nonstop4h 11m
Chicago O'Hare Intl
Mon 8/17
6:42 pm-9:34 pm
Nonstop4h 52m
$360
Showing 1-10 of 60 resultsSorted by cheapest first
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.
SEA-ORD
SEA-BMI
SEA-MLI
SEA-PIA
SEA-MDW
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 Seattle to Illinois
SEA-USIL
SEA-ORD
SEA-BMI
SEA-MLI
SEA-PIA
What is the cheapest month to book a flight from Seattle to Illinois?
Currently, January is the cheapest month in which you can book a flight from Seattle to Illinois (average of $47). Flying from Seattle to Illinois in March is currently the most expensive (average of $686). 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 July 3, 2026.
It’s typically best to fly out from Seattle to Illinois at noon. Doing so could potentially save you 6% on the flight price compared to flying in the morning, which is usually more expensive.
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 July 3, 2026.
The most flights from SEA to USIL are scheduled on a Friday (63 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (25 on average).
How much does it cost to fly round-trip from Seattle to Illinois?
How far ahead should I book a flight from Seattle to Illinois?
The price you pay for your flight from Seattle to Illinois may vary depending on when you book. For the best chance of a lower fare, look to book 81 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
What is the cheapest day to fly from Seattle to Illinois?
Use this chart to determine the cheapest time to fly round-trip from Seattle to Illinois. Price data was last updated on June 27, 2026.
Travelers seeking maximum savings on their Seattle to Illinois flight should consider departing on Saturday afternoons when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
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 July 3, 2026.
Read through reviews of airlines operating flights from Seattle to Illinois, such as Alaska Airlines,Southwest, andDelta. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Comfort
7.8
Boarding
8.1
Overall
7.9
Entertainment
7.0
Food
7.1
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Boarding
8.1
Overall
7.9
Entertainment
7.0
Food
7.1
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Boarding
8.1
Overall
7.9
Entertainment
7.0
Food
7.1
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Boarding
8.1
Overall
7.9
Entertainment
7.0
Food
7.1
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Boarding
8.1
Overall
7.9
Entertainment
7.0
Food
7.1
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Boarding
8.1
Overall
7.9
Entertainment
7.0
Food
7.1
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
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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Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
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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.
Complete your trip
Complete your trip to Illinois by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Seattle to Illinois by cabin class
Find flights from Seattle to Illinois, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Seattle and Illinois flights
Browse other Seattle and Illinois flight options. Last updated on July 3, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Seattle to Illinois flights
Consider these flights traveling from Seattle to Illinois.
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 July 3, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$124 | Average$354 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$124 | Average$318 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$177 | Average$358 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$177 | Average$433 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$180 | Average$430 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$193 | Average$313 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$219 | Average$364 | FlexibilityNo cancel fee | On-time63% |