$145+ Cheap flights from Illinois to Seattle (SEA)
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 11/17. Fares are subject to change and may not be available on all flights or dates of travel.
ORD — SEA
Oct 24 — Oct 311
Round-trip
1 adult, Economy
We work with more than 300 partners to bring you better travel deals
Find cheap flights from Illinois to Seattle 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
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheap flight deals from Illinois to Seattle
Cheapest
Best
Last-minute
One-way
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 September 24, 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 September 24, 2026.
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 10/216:30 am -
1 stop10h 42m
Fri 10/238:00 pm -
1 stop8h 34m
Deal found 9/19![Frontier logo]()
$273
This Kissandfly.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Sat 10/101:16 pm -
Nonstop4h 36m
Sat 10/1711:41 pm -
Nonstop3h 59m
Deal found 9/19![Alaska Airlines logo]()
$275
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/148:01 pm -
1 stop24h 44m
Thu 10/159:16 pm -
1 stop30h 00m
Deal found 9/22![Frontier logo]()
$276
This Gotogate 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/79:30 am -
Nonstop4h 44m
Sat 11/144:27 pm -
1 stop5h 54m
Deal found 9/23![Multiple Airlines logo]()
$277
This Expedia deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 10/213:49 pm -
Nonstop4h 39m
Sat 10/314:27 pm -
1 stop5h 54m
Deal found 9/19![Multiple Airlines logo]()
$278
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 11/76:30 am -
1 stop10h 42m
Wed 11/114:27 pm -
1 stop5h 54m
Deal found 9/19![Frontier logo]()
$279
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Sun 11/15:15 pm -
1 stop18h 30m
Thu 11/59:13 pm -
1 stop30h 00m
Deal found 9/19![Frontier logo]()
$280
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.
Tue 11/179:30 am -
Nonstop4h 44m
Wed 12/24:58 pm -
1 stop5h 55m
Deal found 9/23![Multiple Airlines logo]()
$281
This Expedia deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Tue 10/206:30 am -
1 stop10h 42m
Sat 10/2411:41 pm -
Nonstop3h 59m
Deal found 9/19![Multiple Airlines logo]()
$283
This Mytrip deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/269:00 am -
Nonstop4h 44m
Thu 10/299:13 pm -
1 stop30h 00m
Deal found 9/19![Multiple Airlines logo]()
$285
This Kissandfly.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Sat 10/103:35 pm -
1 stop9h 52m
Sat 10/1711:41 pm -
Nonstop3h 59m
Deal found 9/19![Multiple Airlines logo]()
$286
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.
Sat 10/244:42 pm -
1 stop9h 28m
Tue 10/276:12 am -
1 stop8h 47m
Deal found 9/21![American Airlines logo]()
$288
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 September 24, 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 September 24, 2026.
This United 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/2410:43 am -
1 stop7h 09m
Tue 10/279:05 am -
2 stops12h 08m
Deal found 9/21![United Airlines logo]()
$306
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/1510:05 pm -
Nonstop4h 35m
Tue 10/2012:10 am -
Nonstop3h 55m
Deal found 9/21![Southwest logo]()
$317
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.
Thu 10/156:35 am -
Nonstop4h 45m
Wed 10/217:15 am -
Nonstop4h 15m
Deal found 9/23![Delta logo]()
$317
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.
Thu 10/157:16 pm -
Nonstop4h 43m
Tue 10/2010:33 am -
Nonstop4h 17m
Deal found 9/21![Alaska Airlines logo]()
$317
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.
Sat 10/242:30 pm -
1 stop7h 44m
Mon 10/263:14 pm -
1 stop6h 45m
Deal found 9/20![American Airlines logo]()
$376
This Alaska 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/57:00 am -
Nonstop4h 50m
Mon 11/97:13 am -
1 stop9h 46m
Deal found 9/22![Alaska Airlines logo]()
$327
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/510:00 pm -
Nonstop4h 45m
Thu 11/126:30 am -
2 stops9h 10m
Deal found 9/21![Southwest logo]()
$332
This Delta deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 10/1612:50 pm -
Nonstop4h 35m
Mon 10/1910:39 am -
Nonstop4h 14m
Deal found 9/19![Delta logo]()
$338
This Alaska 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/207:00 am -
Nonstop4h 42m
Mon 10/268:07 pm -
1 stop15h 18m
Deal found 9/22![Alaska Airlines logo]()
$327
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.
Fri 1/88:20 pm -
Nonstop4h 35m
Wed 1/1310:45 am -
Nonstop3h 55m
Deal found 9/23![Southwest logo]()
$338
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.
Fri 10/236:35 am -
Nonstop4h 45m
Mon 10/265:30 pm -
Nonstop4h 04m
Deal found 9/23![Delta logo]()
$338
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 10/225:00 am -
1 stop6h 31m
Mon 10/263:14 pm -
1 stop6h 45m
Deal found 9/20![American Airlines logo]()
$379
This United Airlines deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 1/141:30 pm -
Nonstop4h 46m
Sun 1/1710:54 am -
Nonstop4h 10m
Deal found 9/19![United Airlines logo]()
$383
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 12/75:29 pm -
Nonstop4h 59m
Wed 12/97:05 am -
1 stop9h 55m
Deal found 9/21![Alaska Airlines logo]()
$327
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 10/2110:00 am -
2 stops11h 50m
Sat 10/243:10 pm -
1 stop7h 05m
Deal found 9/23![Southwest logo]()
$342
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.
Tue 10/202:28 pm -
2 stops10h 58m
Tue 10/272:30 pm -
1 stop6h 29m
Deal found 9/20![United Airlines logo]()
$384
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.
Sat 10/319:00 am -
Nonstop4h 44m
Tue 11/39:08 am -
1 stop7h 51m
Deal found 9/23![Alaska Airlines logo]()
$327
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 11/1412:00 pm -
Nonstop4h 33m
Sun 11/2210:39 am -
Nonstop4h 08m
Deal found 9/23![Delta logo]()
$367
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/3112:50 pm -
2 stops7h 40m
Thu 11/55:15 am -
2 stops10h 20m
Deal found 9/20![Southwest logo]()
$347
This United Airlines deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/1710:49 am -
2 stops11h 48m
Sat 10/2410:42 am -
1 stop6h 26m
Deal found 9/19![United Airlines logo]()
$384
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 10/2412:13 pm -
1 stop8h 51m
Mon 10/2611:59 pm -
1 stop9h 27m
Deal found 9/23![Delta logo]()
$376
This United 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/2410:43 am -
2 stops8h 54m
Mon 10/2610:56 pm -
1 stop9h 12m
Deal found 9/21![United Airlines logo]()
$404
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.
Fri 10/169:30 pm -
1 stop13h 35m
Thu 10/2211:35 am -
2 stops11h 40m
Deal found 9/22![Southwest logo]()
$369
This American 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/116:50 pm -
1 stop7h 45m
Sun 11/155:10 am -
1 stop6h 52m
Deal found 9/22![American Airlines logo]()
$494
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.
Wed 10/286:00 am -
1 stop10h 19m
Sat 10/3111:59 pm -
1 stop9h 19m
Deal found 9/21![Delta logo]()
$379
This Alaska 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/152:21 pm -
1 stop9h 12m
Mon 10/1911:31 am -
1 stop10h 28m
Deal found 9/22![Alaska Airlines logo]()
$379
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.
Sun 12/610:20 am -
1 stop10h 55m
Thu 12/1011:20 am -
Nonstop3h 50m
Deal found 9/22![Southwest logo]()
$377
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.
Wed 11/259:00 am -
Nonstop4h 57m
Tue 12/111:35 am -
Nonstop4h 14m
Deal found 9/23![Alaska Airlines logo]()
$383
This American 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/102:37 pm -
1 stop9h 20m
Tue 10/135:00 am -
1 stop7h 07m
Deal found 9/22![American Airlines logo]()
$510
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.
Fri 10/234:26 pm -
1 stop9h 26m
Mon 10/2611:10 pm -
2 stops10h 16m
Deal found 9/21![Delta logo]()
$384
Last-minute flights from Illinois to SeattleDiscover last-minute flight deals from Illinois to Seattle. Data last updated September 24, 2026 and is based on user searches.
Discover last-minute flight deals from Illinois to Seattle. Data last updated September 24, 2026 and is based on user searches.
This Kissandfly.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Sat 10/101:16 pm -
Nonstop4h 36m
Sat 10/1711:41 pm -
Nonstop3h 59m
Deal found 9/19![Alaska Airlines logo]()
$275
This Kissandfly.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Sat 10/103:35 pm -
1 stop9h 52m
Sat 10/1711:41 pm -
Nonstop3h 59m
Deal found 9/19![Multiple Airlines logo]()
$286
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/148:01 pm -
1 stop24h 44m
Thu 10/159:16 pm -
1 stop30h 00m
Deal found 9/22![Frontier logo]()
$276
This Expedia 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/183:30 pm -
1 stop20h 18m
Sat 10/314:27 pm -
1 stop5h 54m
Deal found 9/20![Frontier logo]()
$288
This Expedia deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Tue 10/206:30 am -
1 stop10h 42m
Sat 10/2411:41 pm -
Nonstop3h 59m
Deal found 9/19![Multiple Airlines logo]()
$283
This Cheapflightsfares deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 10/216:30 am -
1 stop10h 42m
Fri 10/238:00 pm -
1 stop8h 34m
Deal found 9/19![Frontier logo]()
$273
This Expedia deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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 10/213:49 pm -
Nonstop4h 39m
Sat 10/314:27 pm -
1 stop5h 54m
Deal found 9/19![Multiple Airlines logo]()
$278
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/216:30 am -
1 stop10h 42m
Wed 10/284:27 pm -
1 stop5h 54m
Deal found 9/21![Frontier logo]()
$279
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.
Sat 10/244:42 pm -
1 stop9h 28m
Tue 10/276:12 am -
1 stop8h 47m
Deal found 9/21![American Airlines logo]()
$288
This Mytrip deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/269:00 am -
Nonstop4h 44m
Thu 10/299:13 pm -
1 stop30h 00m
Deal found 9/19![Multiple Airlines logo]()
$285
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/316:30 am -
1 stop10h 42m
Sun 11/159:13 pm -
1 stop30h 00m
Deal found 9/21![Frontier logo]()
$280
This CheapTickets.ch 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 CheapTickets.ch is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/316:30 am -
1 stop10h 42m
Tue 11/311:42 pm -
Nonstop3h 58m
Deal found 9/23![Multiple Airlines logo]()
$287
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 September 24, 2026.
Search for one-way flight options from Illinois to Seattle. Find affordable one-way fares based on user searches. Data last updated September 24, 2026.
This Kiwi.com 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/176:30 am -
2 stops14h 24m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Frontier logo]()
$145
This Expedia deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” 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.
Mon 1/116:21 am -
1 stop10h 53m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/19![Frontier logo]()
$146
This CheapOair 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/148:01 pm -
1 stop24h 44m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Frontier logo]()
$147
This Mytrip 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/165:15 pm -
2 stops27h 39m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$149
This Gotogate deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/173:49 pm -
Nonstop4h 39m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/19![Alaska Airlines logo]()
$151
This Mytrip 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/186:30 am -
2 stops14h 24m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$156
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 11/77:00 am -
Nonstop4h 50m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/23![Alaska Airlines logo]()
$158
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.
Mon 10/1910:05 pm -
Nonstop4h 35m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Southwest logo]()
$159
This Alaska 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/195:46 pm -
Nonstop4h 42m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Alaska Airlines logo]()
$159
This Mytrip 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/36:30 am -
2 stops14h 24m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Frontier logo]()
$160
This Cheapflightsfares 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/215:19 am -
1 stop9h 18m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Frontier logo]()
$162
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.
Mon 11/1610:15 am -
2 stops10h 20m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Southwest logo]()
$174
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 September 24, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $271 (Kiwi.com) |
One-way from | $145 (Kiwi.com) |
Popular in | June |
Cheapest in | January |
Average price | $398 |
Good round-trip deal | $344 or less |
Good one-way deal | $201 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 7,457,451 searches. Data last updated September 24, 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
Quickest round-trip
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Thu 10/22
12:50 pm-3:25 pm
Nonstop4h 35m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Thu 10/22
7:16 pm-9:59 pm
Nonstop4h 43m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Wed 11/18
8:20 pm-11:07 pm
Nonstop4h 47m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Wed 10/21
12:50 pm-3:25 pm
Nonstop4h 35m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Mon 12/21
6:57 pm-9:56 pm
Nonstop4h 59m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Mon 10/19
7:00 am-9:36 am
Nonstop4h 36m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Tue 10/20
6:35 am-9:20 am
Nonstop4h 45m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$159
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Wed 10/14
6:25 am-2:53 pm
1 stop10h 28m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$164
ChicagoSeattle
ORD Chicago O'Hare Intl - SEA Seattle/Tacoma Intl
ORDSEA
Chicago O'Hare Intl
Tue 10/13
12:55 pm-8:37 pm
1 stop9h 42m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$164
ChicagoSeattle
MDW Chicago Midway - SEA Seattle/Tacoma Intl
MDWSEA
Chicago Midway
Wed 10/14
12:15 pm-6:05 pm
1 stop7h 50m
Seattle/Tacoma Intl
Wed 12/31
12:00 am-2:00 am
Nonstop0h 00m
$169
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.
ORD-SEA
MDW-SEA
PIA-SEA
MLI-SEA
CMI-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
ORD-SEA
MDW-SEA
PIA-SEA
MLI-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 $235). Flying from Illinois to Seattle in June is currently the most expensive (average of $416). 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 September 24, 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 29% 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 September 24, 2026.
The most flights from USIL to SEA are scheduled on a Wednesday (42 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (17 on average).
How much does it cost to fly round-trip from Illinois to Seattle?
Airfare is below average for this route at the moment.
Illinois to Seattle flights typically cost between $284 and $444 in October.The cheapest round-trip price found within the last 5 days was $271 on Frontier (Oct 27-Oct 31).
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 34 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 September 19, 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
Renton
Tacoma
Lacey
Leavenworth
Olympia
Tukwila
Snoqualmie
Puyallup
Lynnwood
Centralia
Kent
Tumwater
Ellensburg
Issaquah
Marysville
Ocean Shores
Lakewood
Fife
Poulsbo
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
Alternative routes
Complete your trip
Flights by cabin class
Other flight options
Popular flights
Seattle flight routes
Top destinations
Alternative routes for Illinois to Seattle
See prices for flight routes from nearby airports that may be better suited for you.
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 September 24, 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 September 24, 2026.
Illinois to Seattle flights
Consider these flights traveling from Illinois to Seattle.
Top 6 airlines flying from Illinois to Seattle
Discover the top 6 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 7,457,451 searches. Data last updated September 24, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$131 | Average$270 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$177 | Average$361 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$177 | Average$356 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$181 | Average$488 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$191 | Average$468 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$233 | Average$387 | FlexibilityNo cancel fee | On-time63% |