$154+ Cheap flights from Ontario to Seattle (SEA)
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/28. Fares are subject to change and may not be available on all flights or dates of travel.
YYZ — SEA
Sep 15 — Sep 221
Round-trip
1 adult, Economy
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Find cheap flights from Ontario 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
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Cheapest flights from Ontario to SeattleExplore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 16, 2026.
Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 16, 2026.
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Fri 9/1112:25 pm -
2 stops9h 20m
Sat 9/127:35 pm -
1 stop7h 00m
Deal found 8/13![WestJet logo]()
$254
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 9/412:25 pm -
2 stops11h 35m
Tue 9/87:00 am -
1 stop7h 15m
Deal found 8/14![WestJet logo]()
$256
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/121:20 pm -
1 stop8h 25m
Wed 9/167:35 pm -
1 stop7h 00m
Deal found 8/14![WestJet logo]()
$261
This Trip.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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.
Fri 9/46:10 pm -
1 stop18h 30m
Tue 9/87:00 am -
1 stop7h 15m
Deal found 8/14![WestJet logo]()
$283
This Justfly.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/188:00 pm -
1 stop16h 40m
Mon 9/287:35 pm -
1 stop8h 30m
Deal found 8/15![WestJet logo]()
$284
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Sat 9/56:10 pm -
1 stop18h 30m
Tue 9/87:00 am -
1 stop7h 15m
Deal found 8/13![WestJet logo]()
$285
This CheapTickets deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/286:55 am -
2 stops14h 50m
Mon 10/57:35 pm -
1 stop7h 00m
Deal found 8/14![WestJet logo]()
$290
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Sun 9/271:20 pm -
1 stop8h 25m
Sun 10/410:30 am -
2 stops10h 50m
Deal found 8/13![WestJet logo]()
$295
This oojo deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/301:20 pm -
1 stop8h 25m
Sun 10/47:35 pm -
1 stop7h 00m
Deal found 8/13![WestJet logo]()
$296
This Kiwi.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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 9/46:45 am -
2 stops17h 15m
Thu 9/107:35 pm -
1 stop8h 30m
Deal found 8/13![WestJet logo]()
$305
This Kiwi.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/56:45 am -
2 stops17h 15m
Sat 9/127:35 pm -
1 stop8h 30m
Deal found 8/13![WestJet logo]()
$313
This Trip.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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.
Fri 9/116:10 pm -
1 stop27h 35m
Wed 9/167:35 pm -
1 stop18h 40m
Deal found 8/15![WestJet logo]()
$314
Best flights from Ontario to SeattleDiscover carefully curated flight deals from Ontario to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 16, 2026.
Discover carefully curated flight deals from Ontario to Seattle that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 16, 2026.
This oojo deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/306:55 am -
2 stops14h 50m
Sun 10/47:35 pm -
1 stop7h 00m
Deal found 8/15![WestJet logo]()
$302
This Delta deal was found by Cheapflights users on 8/11. Clicking the “Pick Dates” 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 11/37:00 am -
1 stop12h 58m
Sat 11/711:45 am -
1 stop9h 12m
Deal found 8/11![Delta logo]()
$355
This Mytrip deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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.
Fri 9/118:40 pm -
1 stop25h 05m
Fri 9/187:35 pm -
1 stop16h 25m
Deal found 8/14![Multiple Airlines logo]()
$398
This United Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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 10/179:15 am -
1 stop9h 36m
Sat 10/177:25 pm -
1 stop9h 51m
Deal found 8/15![United Airlines logo]()
$407
This Air Canada deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/193:30 pm -
1 stop8h 34m
Wed 10/288:40 am -
2 stops10h 12m
Deal found 8/13![Air Canada logo]()
$495
This Alaska Airlines deal was found by Cheapflights users on 8/11. Clicking the “Pick Dates” 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 2/125:15 pm -
Nonstop5h 28m
Sun 2/218:21 am -
Nonstop4h 44m
Deal found 8/11![Alaska Airlines logo]()
$523
This oojo deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/412:25 pm -
2 stops11h 35m
Tue 9/87:00 am -
2 stops26h 30m
Deal found 8/14![WestJet logo]()
$318
This FlightHub deal was found by Cheapflights users on 8/16. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/116:10 pm -
1 stop18h 30m
Mon 9/217:35 pm -
1 stop18h 40m
Deal found 8/16![WestJet logo]()
$325
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 stop11h 45m
Tue 10/2011:59 pm -
1 stop8h 39m
Deal found 8/14![Delta logo]()
$391
This United Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:10 am -
2 stops15h 58m
Tue 9/2210:58 pm -
1 stop11h 11m
Deal found 8/15![United Airlines logo]()
$407
This Mytrip deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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.
Fri 9/116:10 pm -
1 stop18h 30m
Fri 9/1810:30 am -
2 stops8h 39m
Deal found 8/14![Multiple Airlines logo]()
$416
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:10 pm -
1 stop27h 35m
Tue 10/67:35 pm -
1 stop18h 40m
Deal found 8/13![WestJet logo]()
$344
This Delta deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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 10/147:00 am -
1 stop12h 16m
Fri 10/168:25 am -
1 stop11h 57m
Deal found 8/15![Delta logo]()
$393
This United Airlines deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 11/77:00 am -
2 stops15h 17m
Sat 11/145:05 am -
2 stops11h 43m
Deal found 8/14![United Airlines logo]()
$411
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/226:10 pm -
1 stop18h 30m
Sat 10/37:35 pm -
1 stop18h 40m
Deal found 8/13![WestJet logo]()
$344
This Trip.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/88:40 pm -
1 stop25h 05m
Sun 9/138:10 pm -
1 stop20h 40m
Deal found 8/15![Multiple Airlines logo]()
$423
This Delta deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 10/136:00 am -
1 stop11h 45m
Fri 10/168:25 am -
1 stop11h 57m
Deal found 8/14![Delta logo]()
$405
This Trip.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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 9/36:10 pm -
1 stop29h 50m
Sun 9/67:00 am -
1 stop7h 15m
Deal found 8/15![WestJet logo]()
$349
This United Airlines deal was found by Cheapflights users on 8/12. Clicking the “Pick Dates” 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 8/279:45 am -
1 stop9h 22m
Sat 9/55:20 pm -
2 stops14h 20m
Deal found 8/12![United Airlines logo]()
$428
This Mytrip deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 9/288:40 pm -
1 stop25h 05m
Mon 10/53:00 pm -
2 stops21h 00m
Deal found 8/14![Multiple Airlines logo]()
$432
This Delta deal was found by Cheapflights users on 8/11. Clicking the “Pick Dates” 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 9/1012:48 pm -
1 stop12h 17m
Tue 9/158:59 am -
1 stop11h 51m
Deal found 8/11![Delta logo]()
$412
This WestJet deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure WestJet is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/245:55 pm -
1 stop18h 45m
Mon 9/287:35 pm -
1 stop6h 45m
Deal found 8/15![WestJet logo]()
$350
This United Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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 10/196:35 pm -
1 stop9h 40m
Tue 10/2011:13 pm -
1 stop8h 27m
Deal found 8/15![United Airlines logo]()
$430
This Alaska Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/244:55 pm -
Nonstop5h 18m
Sun 9/277:52 am -
Nonstop4h 53m
Deal found 8/15![Alaska Airlines logo]()
$581
This Mytrip deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Sun 10/188:40 pm -
1 stop25h 05m
Fri 10/237:35 pm -
1 stop16h 25m
Deal found 8/13![Multiple Airlines logo]()
$437
This Air Canada deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 1/139:15 am -
2 stops12h 07m
Sat 2/278:15 am -
2 stops10h 32m
Deal found 8/13![Air Canada logo]()
$586
This WestJet deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure WestJet is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/178:15 pm -
1 stop16h 25m
Sat 9/197:35 pm -
1 stop7h 00m
Deal found 8/14![WestJet logo]()
$360
This Delta deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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 10/126:00 am -
1 stop11h 45m
Tue 10/2010:35 pm -
1 stop10h 03m
Deal found 8/15![Delta logo]()
$437
This Alaska Airlines deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/234:55 pm -
Nonstop5h 18m
Sun 9/277:52 am -
Nonstop4h 53m
Deal found 8/15![Alaska Airlines logo]()
$587
This Trip.com deal was found by Cheapflights users on 8/11. Clicking the “Pick Dates” 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.
Wed 10/148:40 pm -
1 stop16h 00m
Mon 10/198:02 am -
1 stop8h 48m
Deal found 8/11![Multiple Airlines logo]()
$447
Last-minute flights from Ontario to SeattleDiscover last-minute flight deals from Ontario to Seattle. Data last updated August 16, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Seattle. Data last updated August 16, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 9/412:25 pm -
2 stops11h 35m
Tue 9/87:00 am -
1 stop7h 15m
Deal found 8/14![WestJet logo]()
$256
This Trip.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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.
Fri 9/46:10 pm -
1 stop18h 30m
Tue 9/87:00 am -
1 stop7h 15m
Deal found 8/14![WestJet logo]()
$283
This Kiwi.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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 9/46:45 am -
2 stops17h 15m
Thu 9/107:35 pm -
1 stop8h 30m
Deal found 8/13![WestJet logo]()
$305
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Sat 9/56:10 pm -
1 stop18h 30m
Tue 9/87:00 am -
1 stop7h 15m
Deal found 8/13![WestJet logo]()
$285
This Kiwi.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/56:45 am -
2 stops17h 15m
Sat 9/127:35 pm -
1 stop8h 30m
Deal found 8/13![WestJet logo]()
$313
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Fri 9/1112:25 pm -
2 stops9h 20m
Sat 9/127:35 pm -
1 stop7h 00m
Deal found 8/13![WestJet logo]()
$254
This Trip.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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.
Fri 9/116:10 pm -
1 stop27h 35m
Wed 9/167:35 pm -
1 stop18h 40m
Deal found 8/15![WestJet logo]()
$314
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/121:20 pm -
1 stop8h 25m
Wed 9/167:35 pm -
1 stop7h 00m
Deal found 8/14![WestJet logo]()
$261
This Justfly.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/188:00 pm -
1 stop16h 40m
Mon 9/287:35 pm -
1 stop8h 30m
Deal found 8/15![WestJet logo]()
$284
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Sun 9/271:20 pm -
1 stop8h 25m
Sun 10/410:30 am -
2 stops10h 50m
Deal found 8/13![WestJet logo]()
$295
This CheapTickets deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/286:55 am -
2 stops14h 50m
Mon 10/57:35 pm -
1 stop7h 00m
Deal found 8/14![WestJet logo]()
$290
This oojo deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure oojo is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/301:20 pm -
1 stop8h 25m
Sun 10/47:35 pm -
1 stop7h 00m
Deal found 8/13![WestJet logo]()
$296
One-way flights from Ontario to SeattleSearch for one-way flight options from Ontario to Seattle. Find affordable one-way fares based on user searches. Data last updated August 16, 2026.
Search for one-way flight options from Ontario to Seattle. Find affordable one-way fares based on user searches. Data last updated August 16, 2026.
This Trip.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/2812:25 pm -
2 stops9h 20m
Deal found 8/15![WestJet logo]()
$154
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/156:45 am -
2 stops15h 00m
Deal found 8/14![WestJet logo]()
$163
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 9/306:45 am -
2 stops15h 00m
Deal found 8/14![WestJet logo]()
$164
This Trip.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” 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.
Wed 9/96:45 am -
2 stops15h 00m
Deal found 8/13![WestJet logo]()
$167
This Flightnetwork deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/271:20 pm -
1 stop8h 25m
Deal found 8/13![WestJet logo]()
$169
This Kiwi.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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 9/116:45 am -
2 stops15h 00m
Deal found 8/15![WestJet logo]()
$171
This FlightHub deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/46:10 pm -
1 stop18h 30m
Deal found 8/14![WestJet logo]()
$179
This Justfly.com deal was found by Cheapflights users on 8/13. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/146:10 pm -
1 stop18h 30m
Deal found 8/13![WestJet logo]()
$180
This Trip.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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.
Wed 9/96:10 pm -
1 stop18h 30m
Deal found 8/14![WestJet logo]()
$181
This Kiwi.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” 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 9/167:15 am -
1 stop14h 30m
Deal found 8/14![WestJet logo]()
$181
This Trip.com deal was found by Cheapflights users on 8/15. Clicking the “Pick Dates” 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.
Sun 9/66:10 pm -
1 stop18h 30m
Deal found 8/15![WestJet logo]()
$182
This Justfly.com deal was found by Cheapflights users on 8/14. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/68:00 pm -
1 stop16h 40m
Deal found 8/14![WestJet logo]()
$182
Find flight deals from Ontario to Seattle
Keep the following information in mind while searching for Ontario to Seattle flight deals. Data was last updated August 16, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $254 (Trip.com) |
One-way from | $154 (Trip.com) |
Popular in | June |
Cheapest in | February |
Average price | $420 |
Good round-trip deal | $568 or less |
Good one-way deal | $260 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Ontario to Seattle that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 16, 2026.
Use the filters below to find and compare flights from Ontario to Seattle that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
OttawaSeattle
YOW Ottawa - SEA Seattle/Tacoma Intl
YOWSEA
Ottawa
Wed 9/30
6:55 am-6:45 pm
2 stops14h 50m
Seattle/Tacoma Intl
Sun 10/4
7:35 pm-5:35 am
1 stop7h 00m
$302
OttawaSeattle
YOW Ottawa - SEA Seattle/Tacoma Intl
YOWSEA
Ottawa
Fri 9/4
12:25 pm-9:00 pm
2 stops11h 35m
Seattle/Tacoma Intl
Tue 9/8
7:00 am-12:30 pm
2 stops26h 30m
$318
HamiltonSeattle
YHM Hamilton - SEA Seattle/Tacoma Intl
YHMSEA
Hamilton
Fri 9/11
6:10 pm-9:40 am
1 stop18h 30m
Seattle/Tacoma Intl
Mon 9/21
7:35 pm-5:15 pm
1 stop18h 40m
$325
HamiltonSeattle
YHM Hamilton - SEA Seattle/Tacoma Intl
YHMSEA
Hamilton
Tue 9/22
6:10 pm-6:45 pm
1 stop27h 35m
Seattle/Tacoma Intl
Tue 10/6
7:35 pm-5:15 pm
1 stop18h 40m
$344
HamiltonSeattle
YHM Hamilton - SEA Seattle/Tacoma Intl
YHMSEA
Hamilton
Tue 9/22
6:10 pm-9:40 am
1 stop18h 30m
Seattle/Tacoma Intl
Sat 10/3
7:35 pm-5:15 pm
1 stop18h 40m
$344
HamiltonSeattle
YHM Hamilton - SEA Seattle/Tacoma Intl
YHMSEA
Hamilton
Thu 9/3
6:10 pm-9:00 pm
1 stop29h 50m
Seattle/Tacoma Intl
Sun 9/6
7:00 am-5:15 pm
1 stop7h 15m
$349
LondonSeattle
YXU London - SEA Seattle/Tacoma Intl
YXUSEA
London
Thu 9/24
5:55 pm-9:40 am
1 stop18h 45m
Seattle/Tacoma Intl
Mon 9/28
7:35 pm-5:20 am
1 stop6h 45m
$350
MontrealSeattle
YUL Montreal Pierre Elliott Trudeau Intl - SEA Seattle/Tacoma Intl
YULSEA
Montreal Pierre Elliott Trudeau Intl
Tue 11/3
7:00 am-4:58 pm
1 stop12h 58m
Seattle/Tacoma Intl
Sat 11/7
11:45 am-11:57 pm
1 stop9h 12m
$355
OttawaSeattle
YOW Ottawa - SEA Seattle/Tacoma Intl
YOWSEA
Ottawa
Thu 9/17
8:15 pm-9:40 am
1 stop16h 25m
Seattle/Tacoma Intl
Sat 9/19
7:35 pm-5:35 am
1 stop7h 00m
$360
MontrealSeattle
YUL Montreal Pierre Elliott Trudeau Intl - SEA Seattle/Tacoma Intl
YULSEA
Montreal Pierre Elliott Trudeau Intl
Sat 10/17
6:00 am-2:45 pm
1 stop11h 45m
Seattle/Tacoma Intl
Tue 10/20
11:59 pm-11:38 am
1 stop8h 39m
$391
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Ontario to Seattle
Have a flexible travel schedule? Discover the best time to fly to Seattle from Ontario with our price prediction graph.
YOW-SEA
YHM-SEA
YUL-SEA
YKF-SEA
YXU-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 Ontario to Seattle
CAON-SEA
YOW-SEA
YHM-SEA
YUL-SEA
YKF-SEA
What is the cheapest month to book a flight from Region of Ontario to Seattle?
Currently, February is the cheapest month in which you can book a flight from Region of Ontario to Seattle (average of $250). Flying from Region of Ontario to Seattle in August is currently the most expensive (average of $472). 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 ON to SEA?
Find hourly flight availability from Ontario 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 August 16, 2026.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Region of Ontario to Seattle as you normally would.
Weekly flight availability from Region of Ontario to Seattle
Explore weekly flight availability from Ontario 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 August 16, 2026.
The most flights from CAON to SEA are scheduled on a Tuesday (4 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (2 on average).
How much does it cost to fly round-trip from Region of Ontario to Seattle?
Airfare is below average for this route at the moment.
Region of Ontario to Seattle flights typically cost between $378 and $657 in September.The cheapest round-trip price found within the last 5 days was $345 on WestJet (Sep 19-Oct 2).
How far ahead should I book a flight from Region of Ontario to Seattle?
The price you pay for your flight from Region of Ontario to Seattle may vary depending on when you book. For the best chance of a lower fare, look to book 85 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
Related info for your journey
Find useful and relevant information for your journey from Ontario 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
Edmonds
Snoqualmie
Lynnwood
Tumwater
Centralia
Puyallup
Marysville
Kent
Ellensburg
Fife
Ocean Shores
Lakewood
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.
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Alternative routes for Ontario 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 Ontario to Seattle by cabin class
Find flights from Ontario to Seattle, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Ontario and Seattle flights
Browse other Ontario and Seattle flight options. Last updated on August 16, 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 August 16, 2026.
Top 5 airlines flying from Ontario to Seattle
Discover the top 5 airlines that operate flights from Ontario to Seattle. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 16, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$197 | Average$388 | FlexibilityNo cancel fee | On-time60% | |
| Cheapest$202 | Average$414 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$209 | Average$432 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$213 | Average$434 | FlexibilityNo cancel fee | On-time67% | |
| Cheapest$219 | Average$443 | FlexibilityNo cancel fee | On-time69% |