$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 12/23. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ORD
Dec 5 — Dec 121
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 November 5, 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 November 5, 2026.
This Kissandfly.com deal was found by Cheapflights users on 11/4. 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 Kissandfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/31:25 pm -
1 stop6h 31m
Wed 12/97:25 am -
1 stop10h 18m
Deal found 11/4![Frontier logo]()
$266
This Delta deal was found by Cheapflights users on 11/3. 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.
Tue 12/15:50 pm -
Nonstop4h 07m
Fri 12/42:04 pm -
1 stop6h 43m
Deal found 11/3![Delta logo]()
$267
This Southwest deal was found by Cheapflights users on 11/3. 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.
Thu 12/36:30 am -
Nonstop3h 55m
Fri 12/48:45 pm -
Nonstop4h 50m
Deal found 11/3![Southwest logo]()
$267
This Priceline deal was found by Cheapflights users on 11/3. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/197:47 pm -
1 stop8h 02m
Wed 12/236:00 am -
Nonstop5h 00m
Deal found 11/3![Multiple Airlines logo]()
$269
This Delta deal was found by Cheapflights users on 11/3. 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.
Tue 12/17:20 am -
Nonstop4h 10m
Mon 12/76:20 am -
1 stop6h 25m
Deal found 11/3![Delta logo]()
$272
This Southwest deal was found by Cheapflights users on 11/4. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/37:40 am -
2 stops7h 40m
Wed 12/95:20 am -
1 stop8h 50m
Deal found 11/4![Southwest logo]()
$272
This Alaska Airlines deal was found by Cheapflights users on 11/3. 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 12/3111:43 am -
Nonstop4h 16m
Fri 1/83:19 pm -
Nonstop4h 43m
Deal found 11/3![Alaska Airlines logo]()
$277
This Southwest deal was found by Cheapflights users on 11/4. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/36:30 am -
Nonstop3h 55m
Sun 12/69:45 pm -
Nonstop4h 50m
Deal found 11/4![Southwest logo]()
$277
This Orbitz deal was found by Cheapflights users on 11/3. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/264:37 pm -
1 stop6h 16m
Wed 12/22:13 pm -
1 stop9h 44m
Deal found 11/3![Multiple Airlines logo]()
$278
This American Airlines deal was found by Cheapflights users on 11/1. 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 12/156:20 am -
Nonstop4h 06m
Sat 12/198:45 pm -
Nonstop4h 57m
Deal found 11/1![American Airlines logo]()
$279
This Southwest deal was found by Cheapflights users on 11/3. 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 11/3012:15 am -
Nonstop3h 50m
Tue 12/810:10 am -
Nonstop4h 40m
Deal found 11/3![Southwest logo]()
$279
This Frontier deal was found by Cheapflights users on 11/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/226:25 pm -
1 stop9h 24m
Sat 1/96:10 am -
1 stop8h 59m
Deal found 11/1![Frontier logo]()
$280
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 November 5, 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 November 5, 2026.
This Delta deal was found by Cheapflights users on 11/4. 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.
Wed 12/91:25 pm -
1 stop6h 31m
Tue 1/52:25 pm -
Nonstop4h 40m
Deal found 11/4![Delta logo]()
$272
This Southwest deal was found by Cheapflights users on 11/3. 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 11/3012:15 am -
Nonstop3h 50m
Tue 12/810:10 am -
Nonstop4h 40m
Deal found 11/3![Southwest logo]()
$279
This United Airlines deal was found by Cheapflights users on 10/31. 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 2/133:50 pm -
1 stop6h 09m
Sat 2/208:45 am -
1 stop7h 45m
Deal found 10/31![United Airlines logo]()
$297
This Alaska Airlines deal was found by Cheapflights users on 10/31. 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 1/2111:45 am -
Nonstop4h 14m
Sat 1/232:13 pm -
1 stop9h 31m
Deal found 10/31![Alaska Airlines logo]()
$309
This American Airlines deal was found by Cheapflights users on 11/1. 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 12/152:07 pm -
1 stop7h 14m
Sat 1/21:53 pm -
1 stop9h 46m
Deal found 11/1![American Airlines logo]()
$521
This Southwest deal was found by Cheapflights users on 11/3. 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 11/3012:15 am -
Nonstop3h 50m
Wed 12/168:45 pm -
Nonstop4h 50m
Deal found 11/3![Southwest logo]()
$284
This Alaska Airlines deal was found by Cheapflights users on 11/4. 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 1/85:50 pm -
Nonstop4h 09m
Fri 1/227:40 am -
1 stop8h 33m
Deal found 11/4![Alaska Airlines logo]()
$309
This Delta deal was found by Cheapflights users on 11/1. 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 12/911:59 pm -
1 stop9h 25m
Wed 12/164:29 pm -
1 stop9h 26m
Deal found 11/1![Delta logo]()
$309
This United Airlines deal was found by Cheapflights users on 11/4. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/1911:44 pm -
Nonstop4h 14m
Tue 12/227:42 pm -
Nonstop4h 50m
Deal found 11/4![United Airlines logo]()
$354
This Alaska Airlines deal was found by Cheapflights users on 11/4. 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 2/1211:05 pm -
1 stop12h 04m
Mon 2/158:00 am -
Nonstop4h 40m
Deal found 11/4![Alaska Airlines logo]()
$327
This Alaska Airlines deal was found by Cheapflights users on 11/2. 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.
Tue 12/295:48 pm -
Nonstop4h 11m
Sun 1/36:00 am -
Nonstop5h 00m
Deal found 11/2![Alaska Airlines logo]()
$327
This Southwest deal was found by Cheapflights users on 11/4. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/235:25 pm -
1 stop9h 00m
Thu 12/248:45 pm -
Nonstop4h 50m
Deal found 11/4![Southwest logo]()
$367
This United Airlines deal was found by Cheapflights users on 11/4. 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 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 12/58:40 am -
2 stops9h 43m
Deal found 11/4![United Airlines logo]()
$371
This United Airlines deal was found by Cheapflights users on 10/31. 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 11/2310:56 pm -
1 stop9h 09m
Thu 11/266:30 am -
1 stop7h 49m
Deal found 10/31![United Airlines logo]()
$379
This Southwest deal was found by Cheapflights users on 11/3. 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 12/258:15 pm -
1 stop7h 40m
Thu 12/318:45 pm -
1 stop13h 45m
Deal found 11/3![Southwest logo]()
$382
This Delta deal was found by Cheapflights users on 11/1. 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 1/272:15 pm -
1 stop7h 40m
Fri 1/299:56 am -
1 stop8h 50m
Deal found 11/1![Delta logo]()
$447
This United Airlines deal was found by Cheapflights users on 11/4. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/202:30 pm -
1 stop6h 43m
Sat 12/58:40 am -
1 stop7h 09m
Deal found 11/4![United Airlines logo]()
$385
This Alaska Airlines deal was found by Cheapflights users on 11/4. 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.
Mon 12/2111:39 pm -
Nonstop4h 01m
Fri 1/87:40 am -
1 stop8h 33m
Deal found 11/4![Alaska Airlines logo]()
$389
This Southwest deal was found by Cheapflights users on 11/4. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/198:15 pm -
1 stop7h 25m
Tue 12/2210:30 pm -
Nonstop4h 50m
Deal found 11/4![Southwest logo]()
$389
This Delta deal was found by Cheapflights users on 11/4. 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 12/311:15 pm -
1 stop8h 22m
Sun 12/61:41 pm -
1 stop7h 02m
Deal found 11/4![Delta logo]()
$447
This American Airlines deal was found by Cheapflights users on 11/3. 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.
Thu 12/1010:51 am -
1 stop7h 34m
Thu 12/176:43 pm -
1 stop6h 59m
Deal found 11/3![American Airlines logo]()
$542
This United Airlines deal was found by Cheapflights users on 11/3. 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 12/111:59 pm -
1 stop9h 16m
Tue 12/82:35 pm -
2 stops11h 09m
Deal found 11/3![United Airlines logo]()
$402
This Alaska Airlines deal was found by Cheapflights users on 11/4. 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.
Tue 1/266:36 am -
1 stop13h 35m
Tue 2/27:40 am -
1 stop8h 33m
Deal found 11/4![Alaska Airlines logo]()
$402
This Southwest deal was found by Cheapflights users on 11/4. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 2/126:45 am -
2 stops9h 10m
Wed 2/173:45 pm -
1 stop9h 10m
Deal found 11/4![Southwest logo]()
$404
This United Airlines deal was found by Cheapflights users on 11/2. 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 11/207:00 am -
Nonstop4h 10m
Mon 11/234:15 pm -
Nonstop4h 48m
Deal found 11/2![United Airlines logo]()
$402
This Southwest deal was found by Cheapflights users on 11/1. 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.
Wed 12/164:40 pm -
2 stops11h 05m
Wed 12/235:00 pm -
2 stops8h 10m
Deal found 11/1![Southwest logo]()
$411
This American Airlines deal was found by Cheapflights users on 11/1. 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 12/2311:59 pm -
1 stop8h 56m
Tue 12/296:43 pm -
1 stop6h 59m
Deal found 11/1![American Airlines logo]()
$610
This Southwest deal was found by Cheapflights users on 11/2. 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.
Sat 11/2111:20 am -
1 stop8h 35m
Tue 11/2410:30 pm -
Nonstop4h 50m
Deal found 11/2![Southwest logo]()
$412
This United Airlines deal was found by Cheapflights users on 11/1. 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 1/912:30 pm -
1 stop6h 40m
Tue 1/126:27 am -
1 stop7h 31m
Deal found 11/1![United Airlines logo]()
$441
This Southwest deal was found by Cheapflights users on 10/31. 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 11/236:45 am -
2 stops9h 00m
Tue 12/11:20 pm -
2 stops11h 30m
Deal found 10/31![Southwest logo]()
$417
Last-minute flights from Seattle to IllinoisDiscover last-minute flight deals from Seattle to Illinois. Data last updated November 5, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Illinois. Data last updated November 5, 2026 and is based on user searches.
This Orbitz deal was found by Cheapflights users on 11/3. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/264:37 pm -
1 stop6h 16m
Wed 12/22:13 pm -
1 stop9h 44m
Deal found 11/3![Multiple Airlines logo]()
$278
This Southwest deal was found by Cheapflights users on 11/3. 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 11/3012:15 am -
Nonstop3h 50m
Tue 12/810:10 am -
Nonstop4h 40m
Deal found 11/3![Southwest logo]()
$279
This Delta deal was found by Cheapflights users on 11/3. 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.
Tue 12/15:50 pm -
Nonstop4h 07m
Fri 12/42:04 pm -
1 stop6h 43m
Deal found 11/3![Delta logo]()
$267
This Delta deal was found by Cheapflights users on 11/3. 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.
Tue 12/15:50 pm -
Nonstop4h 07m
Sun 12/66:20 am -
1 stop6h 25m
Deal found 11/3![Delta logo]()
$272
This Kissandfly.com deal was found by Cheapflights users on 11/4. 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 Kissandfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/31:25 pm -
1 stop6h 31m
Wed 12/97:25 am -
1 stop10h 18m
Deal found 11/4![Frontier logo]()
$266
This Southwest deal was found by Cheapflights users on 11/3. 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.
Thu 12/36:30 am -
Nonstop3h 55m
Fri 12/48:45 pm -
Nonstop4h 50m
Deal found 11/3![Southwest logo]()
$267
This Southwest deal was found by Cheapflights users on 11/4. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/37:40 am -
2 stops7h 40m
Wed 12/95:20 am -
1 stop8h 50m
Deal found 11/4![Southwest logo]()
$272
This Southwest deal was found by Cheapflights users on 11/3. 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.
Thu 12/37:40 am -
1 stop7h 45m
Mon 12/148:45 pm -
Nonstop4h 50m
Deal found 11/3![Southwest logo]()
$277
This American Airlines deal was found by Cheapflights users on 11/1. 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 12/156:20 am -
Nonstop4h 06m
Sat 12/198:45 pm -
Nonstop4h 57m
Deal found 11/1![American Airlines logo]()
$279
This Priceline deal was found by Cheapflights users on 11/3. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/197:47 pm -
1 stop8h 02m
Wed 12/236:00 am -
Nonstop5h 00m
Deal found 11/3![Multiple Airlines logo]()
$269
This Frontier deal was found by Cheapflights users on 11/1. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/226:25 pm -
1 stop9h 24m
Fri 1/86:10 am -
1 stop7h 59m
Deal found 11/1![Frontier logo]()
$280
This Delta deal was found by Cheapflights users on 11/4. 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 12/315:52 pm -
Nonstop4h 07m
Thu 1/72:25 pm -
Nonstop4h 40m
Deal found 11/4![Delta logo]()
$277
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 November 5, 2026.
Search for one-way flight options from Seattle to Illinois. Find affordable one-way fares based on user searches. Data last updated November 5, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 11/2. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/231:37 pm -
1 stop8h 49m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/2![Frontier logo]()
$159
This Frontier deal was found by Cheapflights users on 11/2. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/214:37 pm -
1 stop6h 16m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/2![Frontier logo]()
$160
This American Airlines deal was found by Cheapflights users on 11/2. 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.
Fri 12/186:29 am -
Nonstop4h 06m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/2![American Airlines logo]()
$161
This KAYAK deal was found by Cheapflights users on 11/2. 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/17:20 am -
Nonstop4h 10m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/2![Delta logo]()
$162
This Super.com deal was found by Cheapflights users on 11/2. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/249:53 pm -
1 stop29h 17m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/2![Frontier logo]()
$163
This Southwest deal was found by Cheapflights users on 10/31. 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 12/34:40 pm -
2 stops11h 05m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/31![Southwest logo]()
$164
This Super.com deal was found by Cheapflights users on 11/2. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/309:53 pm -
1 stop29h 06m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/2![Frontier logo]()
$166
This American Airlines deal was found by Cheapflights users on 10/31. 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.
Mon 12/212:01 pm -
Nonstop4h 17m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/31![American Airlines logo]()
$167
This Kiwi.com deal was found by Cheapflights users on 11/1. 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.
Fri 3/56:33 pm -
1 stop9h 37m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/1![Frontier logo]()
$168
This Alaska Airlines deal was found by Cheapflights users on 11/3. 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.
Sat 12/2611:39 pm -
Nonstop4h 01m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/3![Alaska Airlines logo]()
$169
This Southwest deal was found by Cheapflights users on 11/3. 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.
Wed 11/2512:15 am -
Nonstop3h 50m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 11/3![Southwest logo]()
$169
This Trip.com deal was found by Cheapflights users on 10/31. 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.
Thu 12/39:07 pm -
1 stop29h 52m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/31![Frontier logo]()
$170
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 November 5, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $266 (Kissandfly.com) |
One-way from | $159 (Cheapflightsfares) |
Popular in | June |
Cheapest in | February |
Average price | $387 |
Good round-trip deal | $388 or less |
Good one-way deal | $251 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 November 5, 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
Quickest round-trip
SeattleChicago
SEA Seattle/Tacoma Intl - MDW Chicago Midway
SEAMDW
Seattle/Tacoma Intl
Wed 11/25
12:15 am-6:05 am
Nonstop3h 50m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$169
SeattleChicago
SEA Seattle/Tacoma Intl - MDW Chicago Midway
SEAMDW
Seattle/Tacoma Intl
Thu 1/7
1:35 pm-9:45 pm
1 stop6h 10m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$171
SeattleChicago
SEA Seattle/Tacoma Intl - MDW Chicago Midway
SEAMDW
Seattle/Tacoma Intl
Fri 12/4
6:10 am-5:05 pm
2 stops8h 55m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$184
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Thu 12/24
6:28 pm-6:45 pm
1 stop22h 17m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$188
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Sat 1/2
7:15 am-1:29 pm
Nonstop4h 14m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$189
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Sat 12/19
5:52 pm-11:59 pm
Nonstop4h 07m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$189
SeattleChicago
SEA Seattle/Tacoma Intl - MDW Chicago Midway
SEAMDW
Seattle/Tacoma Intl
Sat 1/2
5:50 am-11:40 am
Nonstop3h 50m
Chicago Midway
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$189
SeattlePeoria
SEA Seattle/Tacoma Intl - PIA Greater Peoria
SEAPIA
Seattle/Tacoma Intl
Thu 12/24
11:59 pm-10:52 am
1 stop8h 53m
Greater Peoria
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$190
SeattleChicago
SEA Seattle/Tacoma Intl - ORD Chicago O'Hare Intl
SEAORD
Seattle/Tacoma Intl
Sun 12/20
5:52 pm-11:59 pm
Nonstop4h 07m
Chicago O'Hare Intl
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$194
SeattlePeoria
SEA Seattle/Tacoma Intl - PIA Greater Peoria
SEAPIA
Seattle/Tacoma Intl
Thu 11/26
5:10 am-3:47 pm
1 stop8h 37m
Greater Peoria
Wed 12/31
12:00 am-10:00 pm
Nonstop0h 00m
$195
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-BMI
SEA-PIA
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-BMI
SEA-PIA
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 $257). 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 November 5, 2026.
It’s typically best to fly out from Seattle to Illinois in the afternoon. Doing so could potentially save you 19% 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 November 5, 2026.
The most flights from SEA to USIL are scheduled on a Monday (39 on average). You will have fewer flight options on Sunday, 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?
Airfare is below average for this route at the moment.
Seattle to Illinois flights typically cost between $302 and $476 in December.The cheapest round-trip price found within the last 5 days was $266 on Frontier (Dec 3-Dec 9).
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 60 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 October 31, 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 November 5, 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.
Food
7.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
8.0
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
8.0
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
8.0
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
8.0
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
8.0
Crew
8.6
Reviews
1 / 20
6.0
GoodReza,Jun 2026
TPA - MDW
Food
7.0
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
8.0
Crew
8.6
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 November 5, 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 November 5, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$177 | Average$380 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$177 | Average$357 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$189 | Average$456 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$196 | Average$495 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$208 | Average$315 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$276 | Average$439 | FlexibilityNo cancel fee | On-time63% |