$84+ Cheap flights from Illinois to Seattle (SEA)
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 9/1. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SEA
Jul 6 — Jul 131
Round-trip
1 adult, Economy
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Cheapest flights from Illinois to SeattleExplore the most affordable flight options available from Illinois to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 6, 2026.
Explore the most affordable flight options available from Illinois to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 6, 2026.
This American Airlines deal was found by Cheapflights users on 6/4. 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 9/26:48 pm
PIA
- SEA
1 stop7h 11m
American Airlines
Wed 9/95:30 am
SEA
- PIA
1 stop8h 27m
American Airlines
Deal found 6/4![American Airlines logo]()
$271
This American Airlines deal was found by Cheapflights users on 6/1. 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 8/133:35 pm
STL
- SEA
1 stop8h 46m
American Airlines
Tue 8/186:20 am
SEA
- STL
1 stop9h 17m
American Airlines
Deal found 6/1![American Airlines logo]()
$297
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Wed 8/128:08 pm
STL
- SEA
1 stop15h 09m
Frontier
Mon 8/178:53 pm
SEA
- STL
1 stop19h 15m
Frontier
Deal found 6/3![Frontier logo]()
$300
This American Airlines deal was found by Cheapflights users on 6/1. 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.
Wed 8/198:00 am
STL
- SEA
1 stop8h 03m
American Airlines
Mon 8/246:20 am
SEA
- STL
1 stop9h 17m
American Airlines
Deal found 6/1![American Airlines logo]()
$302
This United Airlines deal was found by Cheapflights users on 6/3. 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.
Tue 9/812:59 pm
STL
- SEA
1 stop8h 16m
United Airlines
Tue 9/158:40 am
SEA
- STL
1 stop5h 54m
United Airlines
Deal found 6/3![United Airlines logo]()
$306
This United Airlines deal was found by Cheapflights users on 6/2. 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.
Mon 7/137:23 pm
STL
- SEA
1 stop7h 52m
United Airlines
Wed 7/152:33 pm
SEA
- STL
1 stop7h 24m
United Airlines
Deal found 6/2![United Airlines logo]()
$307
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 6/307:46 pm
STL
- SEA
1 stop16h 49m
Frontier
Tue 7/78:13 pm
SEA
- STL
1 stop19h 52m
Frontier
Deal found 6/4![Frontier logo]()
$310
This American Airlines deal was found by Cheapflights users on 6/1. 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.
Wed 7/296:58 pm
PIA
- SEA
1 stop7h 54m
American Airlines
Mon 8/312:44 am
SEA
- PIA
1 stop9h 11m
American Airlines
Deal found 6/1![American Airlines logo]()
$310
This United Airlines deal was found by Cheapflights users on 6/3. 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.
Fri 8/145:30 pm
STL
- SEA
1 stop7h 15m
United Airlines
Sun 8/1611:00 pm
SEA
- STL
1 stop7h 39m
United Airlines
Deal found 6/3![United Airlines logo]()
$314
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 8/178:08 pm
STL
- SEA
1 stop15h 40m
Frontier
Fri 8/218:13 pm
SEA
- STL
2 stops21h 10m
Frontier
Deal found 6/4![Frontier logo]()
$316
This United Airlines deal was found by Cheapflights users on 6/2. 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 8/55:10 am
STL
- SEA
1 stop6h 50m
United Airlines
Tue 8/1811:59 pm
SEA
- STL
1 stop8h 11m
United Airlines
Deal found 6/2![United Airlines logo]()
$317
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 8/144:57 pm
STL
- SEA
2 stops22h 20m
Frontier
Mon 8/178:53 pm
SEA
- STL
1 stop19h 15m
Frontier
Deal found 6/4![Frontier logo]()
$318
Best flights from Illinois to SeattleDiscover carefully curated flight deals from Illinois to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 6, 2026.
Discover carefully curated flight deals from Illinois to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 6, 2026.
This American Airlines deal was found by Cheapflights users on 6/3. 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.
Fri 7/106:28 pm
CMI
- SEA
1 stop8h 31m
American Airlines
Wed 7/225:05 am
SEA
- CMI
1 stop7h 11m
American Airlines
Deal found 6/3![American Airlines logo]()
$338
This Delta deal was found by Cheapflights users on 6/3. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/264:24 pm
BMI
- SEA
1 stop9h 33m
Delta
Thu 9/311:05 am
SEA
- BMI
2 stops10h 11m
Delta
Deal found 6/3![Delta logo]()
$351
This United Airlines deal was found by Cheapflights users on 6/1. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/167:00 am
ORD
- SEA
Nonstop4h 40m
United Airlines
Sat 6/205:15 pm
SEA
- ORD
Nonstop4h 07m
United Airlines
Deal found 6/1![United Airlines logo]()
$355
This Alaska Airlines deal was found by Cheapflights users on 6/3. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/166:00 am
ORD
- SEA
Nonstop4h 38m
Alaska Airlines
Fri 7/1712:17 am
SEA
- ORD
Nonstop4h 03m
Alaska Airlines
Deal found 6/3![Alaska Airlines logo]()
$355
This Southwest deal was found by Cheapflights users on 6/1. 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.
Mon 7/2710:00 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Thu 7/305:35 pm
SEA
- MDW
1 stop9h 50m
Southwest
Deal found 6/1![Southwest logo]()
$365
This American Airlines deal was found by Cheapflights users on 6/6. 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 9/125:28 pm
PIA
- SEA
1 stop8h 43m
American Airlines
Mon 9/216:15 am
SEA
- PIA
1 stop8h 43m
American Airlines
Deal found 6/6![American Airlines logo]()
$349
This Delta deal was found by Cheapflights users on 6/1. 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 10/2412:00 pm
BMI
- SEA
1 stop10h 46m
Delta
Mon 10/2611:53 pm
SEA
- BMI
2 stops13h 23m
Delta
Deal found 6/1![Delta logo]()
$351
This Alaska Airlines deal was found by Cheapflights users on 6/1. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/126:00 am
ORD
- SEA
Nonstop4h 38m
Alaska Airlines
Mon 7/2012:17 am
SEA
- ORD
Nonstop4h 03m
Alaska Airlines
Deal found 6/1![Alaska Airlines logo]()
$355
This United Airlines deal was found by Cheapflights users on 6/2. 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.
Sat 8/16:59 am
ORD
- SEA
Nonstop4h 40m
United Airlines
Sun 8/95:15 pm
SEA
- ORD
Nonstop4h 07m
United Airlines
Deal found 6/2![United Airlines logo]()
$355
This Southwest deal was found by Cheapflights users on 6/5. 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.
Sun 7/129:35 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Thu 7/165:30 am
SEA
- MDW
Nonstop3h 55m
Southwest
Deal found 6/5![Southwest logo]()
$366
This Delta deal was found by Cheapflights users on 6/4. 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 10/1512:00 pm
BMI
- SEA
1 stop8h 59m
Delta
Thu 10/2911:53 pm
SEA
- BMI
2 stops13h 23m
Delta
Deal found 6/4![Delta logo]()
$354
This Alaska Airlines deal was found by Cheapflights users on 6/5. 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 6/238:05 pm
ORD
- SEA
Nonstop4h 44m
Alaska Airlines
Wed 7/151:10 pm
SEA
- ORD
Nonstop4h 11m
Alaska Airlines
Deal found 6/5![Alaska Airlines logo]()
$355
This United Airlines deal was found by Cheapflights users on 6/5. 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 11/143:30 pm
PIA
- SEA
1 stop8h 59m
United Airlines
Tue 11/177:00 am
SEA
- PIA
1 stop7h 31m
United Airlines
Deal found 6/5![United Airlines logo]()
$371
This Southwest deal was found by Cheapflights users on 6/3. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/149:50 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Tue 7/2111:05 pm
SEA
- MDW
Nonstop3h 55m
Southwest
Deal found 6/3![Southwest logo]()
$372
This Delta deal was found by Cheapflights users on 6/1. 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.
Fri 10/234:00 pm
BMI
- SEA
1 stop10h 09m
Delta
Mon 10/2611:05 pm
SEA
- BMI
2 stops14h 11m
Delta
Deal found 6/1![Delta logo]()
$354
This Alaska Airlines deal was found by Cheapflights users on 6/5. 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 12/36:00 am
ORD
- SEA
Nonstop4h 39m
Alaska Airlines
Sat 12/55:54 pm
SEA
- ORD
Nonstop4h 05m
Alaska Airlines
Deal found 6/5![Alaska Airlines logo]()
$355
This Southwest deal was found by Cheapflights users on 6/3. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/269:35 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Tue 8/46:35 pm
SEA
- MDW
1 stop8h 25m
Southwest
Deal found 6/3![Southwest logo]()
$381
This United Airlines deal was found by Cheapflights users on 6/3. 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.
Thu 6/255:10 am
STL
- SEA
1 stop6h 50m
United Airlines
Fri 6/268:45 am
SEA
- STL
1 stop7h 32m
United Airlines
Deal found 6/3![United Airlines logo]()
$384
This Alaska Airlines deal was found by Cheapflights users on 6/5. 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 6/238:05 pm
ORD
- SEA
Nonstop4h 44m
Alaska Airlines
Sun 7/1212:17 am
SEA
- ORD
Nonstop4h 03m
Alaska Airlines
Deal found 6/5![Alaska Airlines logo]()
$355
This Delta deal was found by Cheapflights users on 6/1. 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.
Wed 11/257:00 am
ORD
- SEA
Nonstop4h 45m
Delta
Sat 11/285:45 pm
SEA
- ORD
Nonstop4h 01m
Delta
Deal found 6/1![Delta logo]()
$355
This Alaska Airlines deal was found by Cheapflights users on 6/4. 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 7/46:00 am
ORD
- SEA
Nonstop4h 38m
Alaska Airlines
Thu 7/912:17 am
SEA
- ORD
Nonstop4h 03m
Alaska Airlines
Deal found 6/4![Alaska Airlines logo]()
$355
This Southwest deal was found by Cheapflights users on 6/3. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/78:55 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Sun 8/96:50 pm
SEA
- MDW
1 stop8h 50m
Southwest
Deal found 6/3![Southwest logo]()
$394
This Delta deal was found by Cheapflights users on 6/2. 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.
Fri 8/2811:08 am
MLI
- SEA
2 stops12h 57m
Delta
Sun 8/3011:59 pm
SEA
- MLI
2 stops14h 26m
Delta
Deal found 6/2![Delta logo]()
$359
This United Airlines deal was found by Cheapflights users on 6/1. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/87:23 pm
STL
- SEA
1 stop7h 50m
United Airlines
Sun 8/1611:00 pm
SEA
- STL
1 stop7h 39m
United Airlines
Deal found 6/1![United Airlines logo]()
$429
This Alaska Airlines deal was found by Cheapflights users on 6/5. 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 7/76:20 am
ORD
- SEA
1 stop10h 05m
Alaska Airlines
Tue 7/75:48 pm
SEA
- ORD
Nonstop4h 11m
Alaska Airlines
Deal found 6/5![Alaska Airlines logo]()
$360
This Delta deal was found by Cheapflights users on 6/3. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/22:42 pm
ORD
- SEA
1 stop9h 23m
Delta
Thu 8/275:30 pm
SEA
- ORD
Nonstop3h 58m
Delta
Deal found 6/3![Delta logo]()
$363
This Southwest deal was found by Cheapflights users on 6/3. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/276:25 pm
MDW
- SEA
2 stops8h 30m
Southwest
Wed 8/56:40 am
SEA
- MDW
2 stops7h 20m
Southwest
Deal found 6/3![Southwest logo]()
$401
This American Airlines deal was found by Cheapflights users on 6/6. 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 9/174:53 pm
EVV
- SEA
1 stop9h 18m
American Airlines
Mon 9/216:15 am
SEA
- EVV
1 stop8h 08m
American Airlines
Deal found 6/6![American Airlines logo]()
$537
This United Airlines deal was found by Cheapflights users on 6/1. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/95:36 pm
STL
- SEA
1 stop7h 20m
United Airlines
Fri 10/1611:13 pm
SEA
- STL
1 stop9h 35m
United Airlines
Deal found 6/1![United Airlines logo]()
$429
This Delta deal was found by Cheapflights users on 6/3. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/812:40 pm
ORD
- SEA
Nonstop4h 39m
Delta
Sun 10/1112:00 pm
SEA
- ORD
1 stop9h 30m
Delta
Deal found 6/3![Delta logo]()
$363
Last-minute flights from Illinois to SeattleDiscover last-minute flight deals from Illinois to Seattle. Data last updated June 6, 2026 and is based on user searches.
Discover last-minute flight deals from Illinois to Seattle. Data last updated June 6, 2026 and is based on user searches.
This Travelocity deal was found by Cheapflights users on 6/4. 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 Travelocity is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/119:48 pm
ORD
- SEA
1 stop14h 00m
Multiple Airlines
Wed 6/1711:26 am
SEA
- ORD
1 stop10h 10m
Multiple Airlines
Deal found 6/4![Multiple Airlines logo]()
$357
This Booking.com deal was found by Cheapflights users on 6/4. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/119:48 pm
ORD
- SEA
1 stop14h 00m
Frontier
Sun 6/147:41 pm
SEA
- ORD
1 stop23h 02m
Frontier
Deal found 6/4![Frontier logo]()
$362
This Alaska Airlines deal was found by Cheapflights users on 6/4. 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.
Fri 6/126:00 am
ORD
- SEA
Nonstop4h 38m
Alaska Airlines
Fri 6/1211:26 am
SEA
- ORD
1 stop10h 10m
Alaska Airlines
Deal found 6/4![Alaska Airlines logo]()
$360
This Delta deal was found by Cheapflights users on 6/2. 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.
Sat 6/135:55 pm
ORD
- SEA
Nonstop4h 40m
Delta
Wed 6/175:40 pm
SEA
- ORD
Nonstop3h 59m
Delta
Deal found 6/2![Delta logo]()
$355
This Trip.com deal was found by Cheapflights users on 6/1. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/169:48 pm
ORD
- SEA
1 stop18h 30m
Frontier
Tue 6/233:33 pm
SEA
- ORD
1 stop27h 10m
Frontier
Deal found 6/1![Frontier logo]()
$359
This Southwest deal was found by Cheapflights users on 6/5. 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 6/305:35 pm
MDW
- SEA
1 stop9h 05m
Southwest
Wed 8/1911:05 pm
SEA
- MDW
Nonstop4h 00m
Southwest
Deal found 6/5![Southwest logo]()
$363
This Southwest deal was found by Cheapflights users on 6/2. 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 7/35:15 pm
MDW
- SEA
Nonstop4h 30m
Southwest
Fri 7/1011:05 pm
SEA
- MDW
Nonstop3h 55m
Southwest
Deal found 6/2![Southwest logo]()
$355
This American Airlines deal was found by Cheapflights users on 6/3. 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.
Tue 7/76:50 pm
MLI
- SEA
1 stop8h 02m
American Airlines
Tue 7/213:28 pm
SEA
- MLI
1 stop7h 13m
American Airlines
Deal found 6/3![American Airlines logo]()
$349
This American Airlines deal was found by Cheapflights users on 6/4. 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 7/106:28 pm
CMI
- SEA
1 stop8h 31m
American Airlines
Wed 7/225:05 am
SEA
- CMI
1 stop7h 11m
American Airlines
Deal found 6/4![American Airlines logo]()
$338
This Southwest deal was found by Cheapflights users on 6/2. 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.
Tue 7/149:50 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Wed 7/155:00 am
SEA
- MDW
Nonstop3h 55m
Southwest
Deal found 6/2![Southwest logo]()
$357
This Southwest deal was found by Cheapflights users on 6/3. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/149:50 pm
MDW
- SEA
Nonstop4h 35m
Southwest
Wed 7/222:00 pm
SEA
- MDW
1 stop7h 10m
Southwest
Deal found 6/3![Southwest logo]()
$361
This American Airlines deal was found by Cheapflights users on 6/1. 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.
Wed 7/296:58 pm
PIA
- SEA
1 stop7h 54m
American Airlines
Mon 8/312:44 am
SEA
- PIA
1 stop9h 11m
American Airlines
Deal found 6/1![American Airlines logo]()
$310
One-way flights from Illinois to SeattleSearch for one-way flight options from Illinois to Seattle. Find affordable one-way fares based on user searches. Data last updated June 6, 2026.
Search for one-way flight options from Illinois to Seattle. Find affordable one-way fares based on user searches. Data last updated June 6, 2026.
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 9/18:08 pm
STL
- SEA
1 stop15h 40m
Frontier
Deal found 6/4![Frontier logo]()
$84
This American Airlines deal was found by Cheapflights users on 6/1. 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.
Tue 8/2510:16 am
STL
- SEA
1 stop8h 25m
American Airlines
Deal found 6/1![American Airlines logo]()
$108
This Trip.com deal was found by Cheapflights users on 6/4. 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.
Mon 8/318:08 pm
STL
- SEA
1 stop19h 56m
Frontier
Deal found 6/4![Frontier logo]()
$123
This Kiwi.com deal was found by Cheapflights users on 6/3. 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 7/288:08 pm
STL
- SEA
1 stop15h 09m
Frontier
Deal found 6/3![Frontier logo]()
$126
This Kiwi.com deal was found by Cheapflights users on 6/4. 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 9/88:08 pm
STL
- SEA
1 stop30h 19m
Frontier
Deal found 6/4![Frontier logo]()
$131
This Kiwi.com deal was found by Cheapflights users on 6/2. 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.
Tue 8/188:08 pm
STL
- SEA
1 stop15h 40m
Frontier
Deal found 6/2![Frontier logo]()
$134
This United Airlines deal was found by Cheapflights users on 6/1. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/125:10 am
STL
- SEA
1 stop6h 51m
United Airlines
Deal found 6/1![United Airlines logo]()
$135
This Kiwi.com deal was found by Cheapflights users on 6/3. 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.
Mon 8/34:57 pm
STL
- SEA
2 stops44h 11m
Frontier
Deal found 6/3![Frontier logo]()
$137
This Kiwi.com deal was found by Cheapflights users on 6/3. 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 6/308:08 pm
STL
- SEA
1 stop15h 40m
Frontier
Deal found 6/3![Frontier logo]()
$139
This American Airlines deal was found by Cheapflights users on 6/4. 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 10/79:47 am
STL
- SEA
1 stop7h 33m
American Airlines
Deal found 6/4![American Airlines logo]()
$140
This Kiwi.com deal was found by Cheapflights users on 6/2. 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.
Sun 8/1612:31 pm
MLI
- SEA
1 stop24h 08m
Multiple Airlines
Deal found 6/2![Multiple Airlines logo]()
$144
This United Airlines deal was found by Cheapflights users on 6/5. 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 9/11:36 pm
STL
- SEA
2 stops9h 07m
United Airlines
Deal found 6/5![United Airlines logo]()
$145
Find flight deals from Illinois to Seattle
Keep the following information in mind while searching for Illinois to Seattle flight deals. Data was last updated June 6, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $271 (American Airlines) |
One-way from | $84 (Kiwi.com) |
Popular in | June |
Cheapest in | January |
Average price | $376 |
Good round-trip deal | $355 or less |
Good one-way deal | $177 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Illinois to Seattle 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 June 6, 2026.
Use the filters below to find and compare flights from Illinois to Seattle that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
ChampaignSeattle
CMI - SEA
CMISEA
Champaign University-Willard
Fri 7/10
6:28 pm-12:59 am
1 stop8h 31m
Seattle/Tacoma Intl
Wed 7/22
5:05 am-2:16 pm
1 stop7h 11m
$338
PeoriaSeattle
PIA - SEA
PIASEA
Greater Peoria
Sat 9/12
5:28 pm-12:11 am
1 stop8h 43m
Seattle/Tacoma Intl
Mon 9/21
6:15 am-4:58 pm
1 stop8h 43m
$349
BloomingtonSeattle
BMI - SEA
BMISEA
Bloomington-Normal
Wed 8/26
4:24 pm-11:57 pm
1 stop9h 33m
Seattle/Tacoma Intl
Thu 9/3
11:05 am-11:16 pm
2 stops10h 11m
$351
BloomingtonSeattle
BMI - SEA
BMISEA
Bloomington-Normal
Sat 10/24
12:00 pm-8:46 pm
1 stop10h 46m
Seattle/Tacoma Intl
Mon 10/26
11:53 pm-3:16 pm
2 stops13h 23m
$351
BloomingtonSeattle
BMI - SEA
BMISEA
Bloomington-Normal
Thu 10/15
12:00 pm-6:59 pm
1 stop8h 59m
Seattle/Tacoma Intl
Thu 10/29
11:53 pm-3:16 pm
2 stops13h 23m
$354
BloomingtonSeattle
BMI - SEA
BMISEA
Bloomington-Normal
Fri 10/23
4:00 pm-12:09 am
1 stop10h 09m
Seattle/Tacoma Intl
Mon 10/26
11:05 pm-3:16 pm
2 stops14h 11m
$354
ChicagoSeattle
ORD - SEA
ORDSEA
Chicago O'Hare Intl
Tue 6/16
7:00 am-9:40 am
Nonstop4h 40m
Seattle/Tacoma Intl
Sat 6/20
5:15 pm-11:22 pm
Nonstop4h 07m
$355
ChicagoSeattle
ORD - SEA
ORDSEA
Chicago O'Hare Intl
Thu 7/16
6:00 am-8:38 am
Nonstop4h 38m
Seattle/Tacoma Intl
Fri 7/17
12:17 am-6:20 am
Nonstop4h 03m
$355
ChicagoSeattle
ORD - SEA
ORDSEA
Chicago O'Hare Intl
Sun 7/12
6:00 am-8:38 am
Nonstop4h 38m
Seattle/Tacoma Intl
Mon 7/20
12:17 am-6:20 am
Nonstop4h 03m
$355
ChicagoSeattle
ORD - SEA
ORDSEA
Chicago O'Hare Intl
Sat 8/1
6:59 am-9:39 am
Nonstop4h 40m
Seattle/Tacoma Intl
Sun 8/9
5:15 pm-11:22 pm
Nonstop4h 07m
$355
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Illinois to Seattle
Have a flexible travel schedule? Discover the best time to fly to Seattle from Illinois with our price prediction graph.
PIA-SEA
CMI-SEA
MLI-SEA
MDW-SEA
ORD-SEA
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 Illinois to Seattle
USIL-SEA
PIA-SEA
CMI-SEA
MLI-SEA
MDW-SEA
What is the cheapest month to book a flight from Illinois to Seattle?
Currently, January is the cheapest month in which you can book a flight from Illinois to Seattle (average of $88). Flying from Illinois to Seattle in February is currently the most expensive (average of $620). 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 IL to SEA?
Find hourly flight availability from Illinois to Seattle. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 6, 2026.
One of the essential ways to save on airfare from Illinois to Seattle is to remain as flexible as possible. Flights that are at noon tend to be the most expensive. A flight in the evening could potentially save you up to 25% on airfare.
Weekly flight availability from Illinois to Seattle
Explore weekly flight availability from Illinois to Seattle. 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 June 6, 2026.
The most flights from USIL to SEA are scheduled on a Friday (58 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (38 on average).
How much does it cost to fly round-trip from Illinois to Seattle?
How far ahead should I book a flight from Illinois to Seattle?
The price you pay for your flight from Illinois to Seattle may vary depending on when you book. For the best chance of a lower fare, look to book 90 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 Illinois to Seattle?
Use this chart to determine the cheapest time to fly round-trip from Illinois to Seattle. Price data was last updated on May 30, 2026.
Travelers seeking maximum savings on their Illinois to Seattle flight should consider departing on Monday evenings when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
Related info for your journey
Find useful and relevant information for your journey from Illinois to Seattle. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Traveling to a place near Seattle?
Book flights to Seattle if you plan to visit one of these locationsSeaTac
Tacoma
Lacey
Ocean Shores
Leavenworth
Olympia
Edmonds
Snoqualmie
Tumwater
Tukwila
Puyallup
Kent
Lynnwood
Renton
Ellensburg
Fife
Lakewood
Issaquah
Marysville
Shoreline
Browse thousands of different options on Cheapflights for your next trip
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Alternative routes for Illinois to Seattle
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Complete your trip
Complete your trip to Seattle by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Illinois to Seattle by cabin class
Find flights from Illinois to Seattle, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Illinois and Seattle flights
Browse other Illinois and Seattle flight options. Last updated on June 6, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Other flights to Seattle
Explore flights to Seattle departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on June 6, 2026.
Illinois to Seattle flights
Consider these flights traveling from Illinois to Seattle.
Top 7 airlines flying from Illinois to Seattle
Discover the top 7 airlines that operate flights from Illinois to Seattle. 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 June 6, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$84 | Average$278 | FlexibilityNo cancel fee | On-time85% | |
| Cheapest$119 | Average$307 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$131 | Average$258 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$169 | Average$449 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$177 | Average$495 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$177 | Average$438 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$194 | Average$358 | FlexibilityNo cancel fee | On-time63% |