$159+ Cheap flights from Seattle (SEA) to Illinois
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/21. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Oct 25 — Nov 11
Round-trip
1 adult, Economy
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Find cheap flights from Seattle to Illinois with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
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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 September 25, 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 September 25, 2026.
This Expedia deal was found by Cheapflights users on 9/23. 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 10/238:00 pm -
1 stop8h 34m
Mon 10/263:30 pm -
1 stop21h 29m
Deal found 9/23![Frontier logo]()
$277
This Priceline deal was found by Cheapflights users on 9/22. 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.
Thu 12/35:51 pm -
Nonstop4h 08m
Mon 12/77:25 am -
1 stop10h 18m
Deal found 9/22![Multiple Airlines logo]()
$278
This Cheapflightsfares deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/178:00 pm -
1 stop8h 34m
Wed 10/216:30 am -
1 stop10h 42m
Deal found 9/23![Frontier logo]()
$279
This Frontier deal was found by Cheapflights users on 9/22. 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.
Fri 10/304:27 pm -
1 stop5h 54m
Fri 11/66:30 am -
1 stop10h 42m
Deal found 9/22![Frontier logo]()
$280
This Expedia deal was found by Cheapflights users on 9/22. 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 10/79:45 pm -
1 stop29h 31m
Wed 10/218:01 pm -
1 stop24h 44m
Deal found 9/22![Frontier logo]()
$281
This Frontier deal was found by Cheapflights users on 9/21. 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.
Fri 11/64:27 pm -
1 stop5h 54m
Fri 11/136:30 am -
1 stop10h 42m
Deal found 9/21![Frontier logo]()
$282
This Expedia deal was found by Cheapflights users on 9/23. 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.
Sat 10/1711:56 am -
Nonstop4h 24m
Sat 10/246:30 am -
1 stop10h 42m
Deal found 9/23![Multiple Airlines logo]()
$283
This Kiwi.com deal was found by Cheapflights users on 9/24. 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 10/284:27 pm -
1 stop5h 54m
Sat 11/77:00 am -
Nonstop4h 50m
Deal found 9/24![Multiple Airlines logo]()
$284
This Cheapflightsfares deal was found by Cheapflights users on 9/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/248:00 pm -
1 stop8h 34m
Wed 10/286:30 am -
1 stop10h 42m
Deal found 9/25![Frontier logo]()
$285
This Kiwi.com deal was found by Cheapflights users on 9/23. 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 10/284:27 pm -
1 stop5h 54m
Tue 11/36:30 am -
2 stops14h 24m
Deal found 9/23![Frontier logo]()
$286
This Kiwi.com deal was found by Cheapflights users on 9/21. 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 11/114:27 pm -
1 stop5h 54m
Tue 12/16:00 am -
Nonstop4h 57m
Deal found 9/21![Multiple Airlines logo]()
$287
This Frontier deal was found by Cheapflights users on 9/24. 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.
Fri 10/238:00 pm -
1 stop8h 34m
Sat 10/316:30 am -
1 stop10h 42m
Deal found 9/24![Frontier logo]()
$288
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 September 25, 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 September 25, 2026.
This United Airlines deal was found by Cheapflights users on 9/22. 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 11/2110:56 pm -
1 stop9h 12m
Sat 12/56:33 am -
2 stops9h 16m
Deal found 9/22![United Airlines logo]()
$306
This Alaska Airlines deal was found by Cheapflights users on 9/21. 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.
Mon 10/125:49 pm -
Nonstop4h 10m
Mon 10/196:00 am -
Nonstop4h 37m
Deal found 9/21![Alaska Airlines logo]()
$317
This Southwest deal was found by Cheapflights users on 9/25. 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 12/26:30 am -
Nonstop3h 55m
Sat 12/52:05 pm -
Nonstop4h 40m
Deal found 9/25![Southwest logo]()
$317
This Delta deal was found by Cheapflights users on 9/21. 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.
Mon 11/95:55 pm -
Nonstop4h 04m
Fri 11/276:40 am -
Nonstop4h 50m
Deal found 9/21![Delta logo]()
$338
This American Airlines deal was found by Cheapflights users on 9/24. 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 10/162:03 pm -
1 stop6h 55m
Mon 10/195:00 am -
1 stop6h 31m
Deal found 9/24![American Airlines logo]()
$379
This United Airlines deal was found by Cheapflights users on 9/22. 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 10/155:07 pm -
Nonstop4h 03m
Mon 10/198:09 pm -
Nonstop4h 44m
Deal found 9/22![United Airlines logo]()
$317
This Southwest deal was found by Cheapflights users on 9/24. 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 11/41:50 pm -
1 stop6h 50m
Thu 12/108:45 pm -
Nonstop4h 45m
Deal found 9/24![Southwest logo]()
$327
This Alaska Airlines deal was found by Cheapflights users on 9/23. 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 10/3011:56 am -
Nonstop4h 24m
Mon 11/26:35 pm -
Nonstop4h 54m
Deal found 9/23![Alaska Airlines logo]()
$338
This Delta deal was found by Cheapflights users on 9/22. 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 10/2310:39 am -
Nonstop4h 14m
Tue 10/275:30 pm -
Nonstop4h 46m
Deal found 9/22![Delta logo]()
$338
This United Airlines deal was found by Cheapflights users on 9/23. 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 11/1210:50 am -
Nonstop4h 10m
Mon 11/162:30 pm -
1 stop8h 49m
Deal found 9/23![United Airlines logo]()
$327
This Southwest deal was found by Cheapflights users on 9/22. 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 11/56:35 pm -
1 stop7h 50m
Mon 11/910:00 pm -
Nonstop4h 45m
Deal found 9/22![Southwest logo]()
$327
This Alaska Airlines deal was found by Cheapflights users on 9/20. 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 10/2311:56 am -
Nonstop4h 24m
Sat 10/319:00 am -
Nonstop4h 44m
Deal found 9/20![Alaska Airlines logo]()
$338
This American Airlines deal was found by Cheapflights users on 9/24. 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 11/123:10 pm -
1 stop6h 53m
Sun 11/155:37 pm -
1 stop8h 58m
Deal found 9/24![American Airlines logo]()
$379
This Southwest deal was found by Cheapflights users on 9/23. 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 11/125:30 am -
Nonstop3h 50m
Tue 11/1710:15 am -
2 stops9h 35m
Deal found 9/23![Southwest logo]()
$332
This Delta deal was found by Cheapflights users on 9/22. 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 11/176:00 am -
1 stop7h 45m
Sun 11/224:28 pm -
1 stop9h 29m
Deal found 9/22![Delta logo]()
$376
This American Airlines deal was found by Cheapflights users on 9/21. 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 11/63:10 pm -
1 stop6h 53m
Mon 11/95:37 pm -
1 stop8h 58m
Deal found 9/21![American Airlines logo]()
$379
This Alaska Airlines deal was found by Cheapflights users on 9/25. 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 11/711:42 pm -
Nonstop3h 58m
Sat 11/142:07 pm -
1 stop6h 38m
Deal found 9/25![Alaska Airlines logo]()
$348
This Southwest deal was found by Cheapflights users on 9/24. 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 10/2512:10 am -
Nonstop3h 55m
Tue 10/2710:15 am -
Nonstop4h 30m
Deal found 9/24![Southwest logo]()
$338
This Alaska Airlines deal was found by Cheapflights users on 9/25. 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 10/218:49 am -
1 stop8h 04m
Sat 10/242:21 pm -
1 stop10h 12m
Deal found 9/25![Alaska Airlines logo]()
$358
This Delta deal was found by Cheapflights users on 9/22. 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 11/1511:40 pm -
1 stop9h 46m
Sun 11/224:28 pm -
1 stop9h 29m
Deal found 9/22![Delta logo]()
$399
This United Airlines deal was found by Cheapflights users on 9/20. 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 10/141:56 pm -
1 stop6h 42m
Fri 10/232:28 pm -
2 stops10h 31m
Deal found 9/20![United Airlines logo]()
$419
This Delta deal was found by Cheapflights users on 9/23. 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 10/176:00 am -
1 stop7h 44m
Wed 10/214:26 pm -
1 stop9h 26m
Deal found 9/23![Delta logo]()
$399
This Alaska Airlines deal was found by Cheapflights users on 9/23. 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 10/258:32 am -
Nonstop4h 21m
Sat 11/77:00 am -
Nonstop4h 50m
Deal found 9/23![Alaska Airlines logo]()
$367
This Southwest deal was found by Cheapflights users on 9/22. 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 10/2112:10 am -
Nonstop3h 55m
Sun 10/2510:20 pm -
Nonstop4h 35m
Deal found 9/22![Southwest logo]()
$367
This American Airlines deal was found by Cheapflights users on 9/20. 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 12/241:56 pm -
1 stop8h 20m
Wed 12/304:22 pm -
1 stop10h 36m
Deal found 9/20![American Airlines logo]()
$449
This Alaska Airlines deal was found by Cheapflights users on 9/23. 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 10/255:49 pm -
Nonstop4h 10m
Thu 11/56:35 pm -
Nonstop4h 54m
Deal found 9/23![Alaska Airlines logo]()
$367
This Southwest deal was found by Cheapflights users on 9/23. 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 10/2912:10 am -
Nonstop3h 55m
Fri 10/3011:50 am -
1 stop8h 20m
Deal found 9/23![Southwest logo]()
$369
This United Airlines deal was found by Cheapflights users on 9/24. 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 11/1110:56 pm -
1 stop9h 12m
Sun 11/155:35 pm -
1 stop7h 32m
Deal found 9/24![United Airlines logo]()
$460
This American Airlines deal was found by Cheapflights users on 9/24. 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 11/113:10 pm -
1 stop6h 49m
Sun 11/155:00 am -
1 stop6h 39m
Deal found 9/24![American Airlines logo]()
$496
This Southwest deal was found by Cheapflights users on 9/23. 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 11/28:40 pm -
1 stop7h 15m
Sun 11/810:00 pm -
Nonstop4h 45m
Deal found 9/23![Southwest logo]()
$377
Last-minute flights from Seattle to IllinoisDiscover last-minute flight deals from Seattle to Illinois. Data last updated September 25, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Illinois. Data last updated September 25, 2026 and is based on user searches.
This Expedia deal was found by Cheapflights users on 9/22. 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 10/79:45 pm -
1 stop29h 31m
Wed 10/218:01 pm -
1 stop24h 44m
Deal found 9/22![Frontier logo]()
$281
This Cheapflightsfares deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/178:00 pm -
1 stop8h 34m
Wed 10/216:30 am -
1 stop10h 42m
Deal found 9/23![Frontier logo]()
$279
This Expedia deal was found by Cheapflights users on 9/23. 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.
Sat 10/1711:56 am -
Nonstop4h 24m
Sat 10/246:30 am -
1 stop10h 42m
Deal found 9/23![Multiple Airlines logo]()
$283
This Southwest deal was found by Cheapflights users on 9/23. 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 10/2112:10 am -
Nonstop3h 55m
Mon 10/2610:05 pm -
Nonstop4h 35m
Deal found 9/23![Southwest logo]()
$317
This Expedia deal was found by Cheapflights users on 9/23. 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 10/238:00 pm -
1 stop8h 34m
Mon 10/263:30 pm -
1 stop21h 29m
Deal found 9/23![Frontier logo]()
$277
This Frontier deal was found by Cheapflights users on 9/24. 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.
Fri 10/238:00 pm -
1 stop8h 34m
Sat 10/316:30 am -
1 stop10h 42m
Deal found 9/24![Frontier logo]()
$288
This Cheapflightsfares deal was found by Cheapflights users on 9/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/248:00 pm -
1 stop8h 34m
Wed 10/286:30 am -
1 stop10h 42m
Deal found 9/25![Frontier logo]()
$285
This Kiwi.com deal was found by Cheapflights users on 9/24. 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 10/284:27 pm -
1 stop5h 54m
Sat 11/77:00 am -
Nonstop4h 50m
Deal found 9/24![Multiple Airlines logo]()
$284
This Kiwi.com deal was found by Cheapflights users on 9/23. 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 10/284:27 pm -
1 stop5h 54m
Tue 11/36:30 am -
2 stops14h 24m
Deal found 9/23![Frontier logo]()
$286
This Kiwi.com deal was found by Cheapflights users on 9/23. 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 10/284:27 pm -
1 stop5h 54m
Thu 11/53:59 pm -
Nonstop4h 49m
Deal found 9/23![Multiple Airlines logo]()
$290
This Frontier deal was found by Cheapflights users on 9/22. 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.
Fri 10/304:27 pm -
1 stop5h 54m
Fri 11/66:30 am -
1 stop10h 42m
Deal found 9/22![Frontier logo]()
$280
This Travelocity deal was found by Cheapflights users on 9/22. 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.
Sat 10/314:27 pm -
1 stop5h 54m
Mon 11/27:00 am -
Nonstop4h 50m
Deal found 9/22![Multiple Airlines logo]()
$278
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 September 25, 2026.
Search for one-way flight options from Seattle to Illinois. Find affordable one-way fares based on user searches. Data last updated September 25, 2026.
This Alaska Airlines deal was found by Cheapflights users on 9/25. 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 10/2111:56 am -
Nonstop4h 24m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/25![Alaska Airlines logo]()
$159
This Southwest deal was found by Cheapflights users on 9/23. 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 10/2012:10 am -
Nonstop3h 55m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Southwest logo]()
$159
This Super.com deal was found by Cheapflights users on 9/20. 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.
Tue 10/138:00 pm -
1 stop8h 34m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/20![Frontier logo]()
$161
This Super.com deal was found by Cheapflights users on 9/21. 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.
Fri 11/204:37 pm -
1 stop6h 16m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$163
This United Airlines deal was found by Cheapflights users on 9/24. 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 10/1912:00 pm -
1 stop9h 27m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/24![United Airlines logo]()
$164
This Frontier deal was found by Cheapflights users on 9/21. 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.
Sun 11/224:37 pm -
1 stop6h 16m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$165
This Kiwi.com deal was found by Cheapflights users on 9/21. 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 11/48:09 pm -
2 stops26h 12m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$166
This Cheapflightsfares deal was found by Cheapflights users on 9/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/178:00 pm -
1 stop8h 34m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/25![Frontier logo]()
$167
This Cheapflightsfares deal was found by Cheapflights users on 9/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/159:16 pm -
1 stop30h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/24![Frontier logo]()
$168
This United Airlines deal was found by Cheapflights users on 9/23. 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 11/38:30 am -
1 stop8h 08m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![United Airlines logo]()
$169
This KAYAK deal was found by Cheapflights users on 9/21. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/265:30 pm -
Nonstop4h 04m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Delta logo]()
$170
This Booking.com deal was found by Cheapflights users on 9/24. 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.
Sun 11/89:13 pm -
1 stop30h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/24![Frontier logo]()
$171
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 September 25, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $277 (Expedia) |
One-way from | $159 (Alaska Airlines) |
Popular in | June |
Cheapest in | February |
Average price | $376 |
Good round-trip deal | $356 or less |
Good one-way deal | $204 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 7,457,451 searches. Data last updated September 25, 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
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Wed 11/18
5:55 pm-11:59 pm
Nonstop4h 04m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Sat 10/31
8:32 am-2:53 pm
Nonstop4h 21m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Mon 10/19
7:00 am-1:15 pm
Nonstop4h 15m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Tue 11/17
11:34 pm-5:35 am
Nonstop4h 01m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - MDW Chicago Midway
SEAMDW
Seattle/Tacoma Intl
Tue 10/20
12:10 am-6:05 am
Nonstop3h 55m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Thu 12/24
5:52 pm-11:59 pm
Nonstop4h 07m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Mon 11/23
11:58 pm-5:56 am
Nonstop3h 58m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
Quickest round-trip
SeattleChicago
SEA Seattle/Tacoma Intl - MDW Chicago Midway
SEAMDW
Seattle/Tacoma Intl
Sun 11/8
12:15 am-6:05 am
Nonstop3h 50m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Wed 10/21
11:56 am-6:20 pm
Nonstop4h 24m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Sat 10/31
7:45 am-2:00 pm
Nonstop4h 15m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$159
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-MDW
SEA-PIA
SEA-BMI
SEA-MLI
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-MDW
SEA-PIA
SEA-BMI
What is the cheapest month to book a flight from Seattle to Illinois?
Currently, February is the cheapest month in which you can book a flight from Seattle to Illinois (average of $262). Flying from Seattle to Illinois in June is currently the most expensive (average of $419). 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 September 25, 2026.
It’s typically best to fly out from Seattle to Illinois in the evening. Doing so could potentially save you 5% on the flight price compared to flying at noon, 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 September 25, 2026.
The most flights from SEA to USIL are scheduled on a Wednesday (51 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (20 on average).
How much does it cost to fly round-trip from Seattle to Illinois?
Airfare is below average for this route at the moment.
Seattle to Illinois flights typically cost between $314 and $462 in October.The cheapest round-trip price found within the last 5 days was $277 on Frontier (Oct 23-Oct 26).
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 30 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 September 19, 2026.
Travelers seeking maximum savings on their Seattle to Illinois flight should consider departing on Tuesday at noon 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 September 25, 2026.
Read through reviews of airlines operating flights from Seattle to Illinois, such as Southwest,Alaska Airlines, andDelta. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
8.1
Entertainment
7.5
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Entertainment
7.5
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Entertainment
7.5
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Entertainment
7.5
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Entertainment
7.5
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Boarding
8.1
Entertainment
7.5
Crew
8.6
Overall
8.0
Comfort
8.0
Food
7.0
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Related info for your journey
Find useful and relevant information for your journey from Seattle to Illinois. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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Alternative routes for Seattle to Illinois
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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 September 25, 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 6 airlines flying from Seattle to Illinois
Discover the top 6 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 7,457,451 searches. Data last updated September 25, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$168 | Average$374 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$177 | Average$376 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$177 | Average$453 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$193 | Average$313 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$195 | Average$476 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$257 | Average$429 | FlexibilityNo cancel fee | On-time63% |