$158+ Cheap flights from Seattle (SEA) to Ontario
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 9/6. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
Jul 10 — Jul 171
Round-trip
1 adult, Economy
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Cheapest flights from Seattle to OntarioExplore the most affordable flight options available from Seattle to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 10, 2026.
Explore the most affordable flight options available from Seattle to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 10, 2026.
This CheapOair deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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.
Fri 10/27:35 pm
SEA
- YYZ
1 stop7h 10m
WestJet
Wed 10/71:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/8![WestJet logo]()
$369
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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.
Thu 7/27:00 am
SEA
- YYZ
1 stop7h 10m
WestJet
Tue 7/141:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/9![WestJet logo]()
$370
This Jettzy deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Jettzy is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/97:35 pm
SEA
- YYZ
1 stop7h 10m
WestJet
Wed 11/187:45 am
YYZ
- SEA
1 stop8h 35m
WestJet
Deal found 6/10![WestJet logo]()
$371
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/77:35 pm
SEA
- YYZ
1 stop7h 10m
WestJet
Tue 7/141:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/9![WestJet logo]()
$374
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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.
Thu 7/27:00 am
SEA
- YYZ
2 stops11h 10m
WestJet
Thu 7/93:50 pm
YYZ
- SEA
1 stop8h 10m
WestJet
Deal found 6/10![WestJet logo]()
$375
This Jettzy deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Jettzy is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/95:40 am
SEA
- YYZ
2 stops10h 33m
Multiple Airlines
Wed 11/187:45 am
YYZ
- SEA
1 stop8h 35m
Multiple Airlines
Deal found 6/10![Multiple Airlines logo]()
$376
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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.
Thu 9/247:35 pm
SEA
- YYZ
1 stop7h 10m
WestJet
Mon 9/281:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/9![WestJet logo]()
$377
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/110:30 am
SEA
- YYZ
1 stop9h 15m
WestJet
Thu 7/912:00 pm
YYZ
- SEA
2 stops9h 45m
WestJet
Deal found 6/10![WestJet logo]()
$378
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/237:00 am
SEA
- YYZ
2 stops11h 10m
WestJet
Sat 9/51:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/9![WestJet logo]()
$379
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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.
Thu 7/210:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Wed 7/83:50 pm
YYZ
- SEA
1 stop8h 10m
WestJet
Deal found 6/10![WestJet logo]()
$380
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/310:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Wed 7/83:50 pm
YYZ
- SEA
1 stop8h 10m
WestJet
Deal found 6/10![WestJet logo]()
$382
This CheapOair deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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.
Sun 10/47:35 pm
SEA
- YUL
1 stop8h 30m
WestJet
Sat 10/106:45 am
YUL
- SEA
2 stops15h 00m
WestJet
Deal found 6/8![WestJet logo]()
$383
Best flights from Seattle to OntarioDiscover carefully curated flight deals from Seattle to Ontario that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 10, 2026.
Discover carefully curated flight deals from Seattle to Ontario that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated June 10, 2026.
This Trip.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 8/147:35 pm
SEA
- YKF
1 stop21h 15m
WestJet
Mon 8/178:40 pm
YKF
- SEA
1 stop16h 00m
WestJet
Deal found 6/10![WestJet logo]()
$421
This United Airlines deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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 9/178:00 am
SEA
- YYZ
Nonstop4h 50m
United Airlines
Sun 9/207:30 am
YYZ
- SEA
1 stop9h 58m
United Airlines
Deal found 6/9![United Airlines logo]()
$465
This Delta deal was found by Cheapflights users on 6/7. Clicking the “Pick Dates” 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 9/239:10 am
SEA
- YUL
1 stop11h 47m
Delta
Sat 9/267:00 am
YUL
- SEA
1 stop8h 58m
Delta
Deal found 6/7![Delta logo]()
$473
This United deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/1611:50 pm
SEA
- YUL
1 stop14h 17m
Multiple Airlines
Sun 11/2210:30 am
YUL
- SEA
2 stops13h 24m
Multiple Airlines
Deal found 6/9![Multiple Airlines logo]()
$481
This Air Canada deal was found by Cheapflights users on 6/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Air Canada is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/45:45 am
SEA
- YXU
2 stops8h 57m
Air Canada
Sun 11/19:45 am
YXU
- SEA
2 stops11h 37m
Air Canada
Deal found 6/6![Air Canada logo]()
$565
This Alaska Airlines deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/16:02 am
SEA
- YYZ
1 stop8h 26m
Alaska Airlines
Thu 7/93:14 pm
YYZ
- SEA
1 stop9h 20m
Alaska Airlines
Deal found 6/10![Alaska Airlines logo]()
$593
This CheapOair deal was found by Cheapflights users on 6/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/410:30 am
SEA
- YUL
2 stops10h 55m
WestJet
Sat 10/106:45 am
YUL
- SEA
2 stops15h 00m
WestJet
Deal found 6/5![WestJet logo]()
$450
This Delta deal was found by Cheapflights users on 6/7. Clicking the “Pick Dates” 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 9/239:10 am
SEA
- YUL
1 stop11h 47m
Delta
Wed 9/305:10 pm
YUL
- SEA
1 stop7h 52m
Delta
Deal found 6/7![Delta logo]()
$473
This United Airlines deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 9/285:21 pm
SEA
- YTZ
2 stops13h 45m
United Airlines
Wed 9/307:20 pm
YTZ
- SEA
1 stop17h 16m
United Airlines
Deal found 6/8![United Airlines logo]()
$476
This Booking.com deal was found by Cheapflights users on 6/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/277:35 pm
SEA
- YUL
1 stop8h 30m
WestJet
Sun 8/308:00 pm
YUL
- SEA
1 stop25h 45m
WestJet
Deal found 6/5![WestJet logo]()
$453
This United deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/107:00 am
SEA
- YYZ
1 stop9h 37m
Multiple Airlines
Mon 7/139:10 pm
YYZ
- SEA
1 stop15h 57m
Multiple Airlines
Deal found 6/8![Multiple Airlines logo]()
$505
This United Airlines deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2311:00 pm
SEA
- YUL
1 stop8h 40m
United Airlines
Mon 10/52:20 pm
YUL
- SEA
1 stop9h 17m
United Airlines
Deal found 6/8![United Airlines logo]()
$478
This Delta deal was found by Cheapflights users on 6/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/111:10 pm
SEA
- YYZ
1 stop6h 45m
Delta
Wed 9/95:50 pm
YYZ
- SEA
1 stop7h 26m
Delta
Deal found 6/5![Delta logo]()
$496
This CheapOair deal was found by Cheapflights users on 6/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/97:35 pm
SEA
- YKF
1 stop21h 15m
WestJet
Tue 7/148:40 pm
YKF
- SEA
1 stop16h 00m
WestJet
Deal found 6/6![WestJet logo]()
$456
This Mytrip deal was found by Cheapflights users on 6/7. Clicking the “Pick Dates” 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 7/217:00 am
SEA
- YOW
1 stop29h 20m
Multiple Airlines
Thu 7/234:00 pm
YOW
- SEA
3 stops20h 40m
Multiple Airlines
Deal found 6/7![Multiple Airlines logo]()
$511
This United Airlines deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 9/2411:59 pm
SEA
- YUL
1 stop11h 51m
United Airlines
Mon 10/56:35 pm
YUL
- SEA
1 stop9h 40m
United Airlines
Deal found 6/8![United Airlines logo]()
$478
This Delta deal was found by Cheapflights users on 6/7. Clicking the “Pick Dates” 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 9/16:00 am
SEA
- YYZ
1 stop8h 19m
Delta
Sun 9/66:10 am
YYZ
- SEA
1 stop7h 21m
Delta
Deal found 6/7![Delta logo]()
$496
This Booking.com deal was found by Cheapflights users on 6/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/237:00 am
SEA
- YKF
1 stop9h 50m
WestJet
Tue 7/288:40 pm
YKF
- SEA
1 stop27h 20m
WestJet
Deal found 6/7![WestJet logo]()
$458
This Air Canada deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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 10/147:20 pm
SEA
- YXU
2 stops11h 00m
Air Canada
Thu 10/153:30 pm
YXU
- SEA
1 stop8h 34m
Air Canada
Deal found 6/9![Air Canada logo]()
$618
This Mytrip deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 7/17:00 am
SEA
- YHM
1 stop7h 15m
Multiple Airlines
Thu 7/96:10 am
YHM
- SEA
3 stops17h 50m
Multiple Airlines
Deal found 6/8![Multiple Airlines logo]()
$519
This United Airlines deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 9/287:00 am
SEA
- YUL
1 stop7h 30m
United Airlines
Mon 10/56:35 pm
YUL
- SEA
1 stop9h 40m
United Airlines
Deal found 6/8![United Airlines logo]()
$478
This Delta deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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 11/107:30 am
SEA
- YYZ
2 stops12h 34m
Delta
Sat 11/149:45 am
YYZ
- SEA
1 stop7h 38m
Delta
Deal found 6/9![Delta logo]()
$511
This Booking.com deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/77:35 pm
SEA
- YOW
1 stop20h 45m
WestJet
Tue 7/146:55 am
YOW
- SEA
2 stops14h 50m
WestJet
Deal found 6/8![WestJet logo]()
$465
This Air Canada deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 10/217:20 pm
SEA
- YTS
2 stops11h 52m
Air Canada
Sat 10/245:15 am
YTS
- SEA
2 stops16h 17m
Air Canada
Deal found 6/8![Air Canada logo]()
$627
This United deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/1011:00 pm
SEA
- YUL
1 stop14h 10m
Multiple Airlines
Wed 7/226:00 am
YUL
- SEA
1 stop18h 07m
Multiple Airlines
Deal found 6/10![Multiple Airlines logo]()
$521
This United Airlines deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/2811:00 pm
SEA
- YTZ
1 stop8h 06m
United Airlines
Tue 9/17:20 pm
YTZ
- SEA
1 stop17h 16m
United Airlines
Deal found 6/9![United Airlines logo]()
$487
This FlightHub deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 8/217:00 am
SEA
- YHM
1 stop7h 15m
WestJet
Mon 8/246:10 pm
YHM
- SEA
1 stop18h 30m
WestJet
Deal found 6/10![WestJet logo]()
$467
This Delta deal was found by Cheapflights users on 6/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/258:59 pm
SEA
- YYZ
2 stops10h 26m
Delta
Sat 8/299:45 am
YYZ
- SEA
1 stop7h 49m
Delta
Deal found 6/6![Delta logo]()
$524
This Air Canada deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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.
Tue 9/227:20 pm
SEA
- YQT
2 stops12h 28m
Air Canada
Sat 9/265:15 am
YQT
- SEA
2 stops12h 07m
Air Canada
Deal found 6/9![Air Canada logo]()
$657
This United Airlines deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/2811:00 pm
SEA
- YYZ
1 stop7h 54m
United Airlines
Tue 9/112:25 pm
YYZ
- SEA
1 stop9h 42m
United Airlines
Deal found 6/9![United Airlines logo]()
$496
Last-minute flights from Seattle to OntarioDiscover last-minute flight deals from Seattle to Ontario. Data last updated June 10, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Ontario. Data last updated June 10, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/307:35 pm
SEA
- YYZ
1 stop8h 20m
WestJet
Thu 7/912:00 pm
YYZ
- SEA
2 stops9h 45m
WestJet
Deal found 6/10![WestJet logo]()
$387
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/110:30 am
SEA
- YYZ
1 stop9h 15m
WestJet
Thu 7/912:00 pm
YYZ
- SEA
2 stops9h 45m
WestJet
Deal found 6/10![WestJet logo]()
$378
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/17:00 am
SEA
- YYZ
1 stop8h 55m
WestJet
Thu 7/1612:00 pm
YYZ
- SEA
2 stops9h 45m
WestJet
Deal found 6/10![WestJet logo]()
$385
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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.
Thu 7/27:00 am
SEA
- YYZ
1 stop7h 10m
WestJet
Tue 7/141:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/9![WestJet logo]()
$370
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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.
Thu 7/27:00 am
SEA
- YYZ
2 stops11h 10m
WestJet
Thu 7/93:50 pm
YYZ
- SEA
1 stop8h 10m
WestJet
Deal found 6/10![WestJet logo]()
$375
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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.
Thu 7/210:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Wed 7/83:50 pm
YYZ
- SEA
1 stop8h 10m
WestJet
Deal found 6/10![WestJet logo]()
$380
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/310:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Wed 7/83:50 pm
YYZ
- SEA
1 stop8h 10m
WestJet
Deal found 6/10![WestJet logo]()
$382
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/37:35 pm
SEA
- YUL
1 stop8h 30m
WestJet
Thu 7/96:45 am
YUL
- SEA
2 stops15h 00m
WestJet
Deal found 6/10![WestJet logo]()
$403
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/77:35 pm
SEA
- YYZ
1 stop7h 10m
WestJet
Tue 7/141:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/9![WestJet logo]()
$374
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/810:30 am
SEA
- YYZ
1 stop7h 45m
WestJet
Tue 7/141:30 pm
YYZ
- SEA
1 stop8h 15m
WestJet
Deal found 6/10![WestJet logo]()
$383
This Gotogate deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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.
Mon 7/137:35 pm
SEA
- YUL
1 stop8h 30m
Multiple Airlines
Tue 7/2110:40 am
YUL
- SEA
2 stops13h 27m
Multiple Airlines
Deal found 6/10![Multiple Airlines logo]()
$405
This Booking.com deal was found by Cheapflights users on 6/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/167:00 am
SEA
- YOW
1 stop9h 20m
WestJet
Thu 7/231:20 pm
YOW
- SEA
1 stop8h 25m
WestJet
Deal found 6/7![WestJet logo]()
$403
One-way flights from Seattle to OntarioSearch for one-way flight options from Seattle to Ontario. Find affordable one-way fares based on user searches. Data last updated June 10, 2026.
Search for one-way flight options from Seattle to Ontario. Find affordable one-way fares based on user searches. Data last updated June 10, 2026.
This CheapOair deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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.
Sun 9/610:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Deal found 6/8![WestJet logo]()
$158
This Air Canada deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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 9/168:00 am
SEA
- YUL
1 stop8h 21m
Air Canada
Deal found 6/8![Air Canada logo]()
$170
This Booking.com deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/1510:30 am
SEA
- YUL
2 stops10h 55m
WestJet
Deal found 6/8![WestJet logo]()
$173
This Booking.com deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/217:35 pm
SEA
- YUL
1 stop8h 30m
WestJet
Deal found 6/8![WestJet logo]()
$178
This oojo deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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.
Sat 8/110:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Deal found 6/9![WestJet logo]()
$179
This Booking.com deal was found by Cheapflights users on 6/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/2910:30 am
SEA
- YYZ
1 stop9h 15m
WestJet
Deal found 6/6![WestJet logo]()
$181
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 8/2210:30 am
SEA
- YYZ
2 stops10h 29m
WestJet
Deal found 6/10![WestJet logo]()
$182
This CheapOair deal was found by Cheapflights users on 6/8. Clicking the “Pick Dates” 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.
Sun 9/67:00 am
SEA
- YHM
1 stop7h 15m
WestJet
Deal found 6/8![WestJet logo]()
$182
This Kiwi.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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 7/187:35 pm
SEA
- YUL
1 stop8h 30m
WestJet
Deal found 6/9![WestJet logo]()
$182
This Kiwi.com deal was found by Cheapflights users on 6/10. Clicking the “Pick Dates” 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 7/37:35 pm
SEA
- YUL
1 stop8h 30m
WestJet
Deal found 6/10![WestJet logo]()
$183
This Justfly.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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.
Wed 7/810:30 am
SEA
- YYZ
1 stop9h 15m
WestJet
Deal found 6/9![WestJet logo]()
$184
This Justfly.com deal was found by Cheapflights users on 6/9. Clicking the “Pick Dates” 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 7/197:00 am
SEA
- YHM
1 stop7h 15m
WestJet
Deal found 6/9![WestJet logo]()
$184
Find flight deals from Seattle to Ontario
Keep the following information in mind while searching for Seattle to Ontario flight deals. Data was last updated June 10, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $369 (CheapOair) |
One-way from | $158 (CheapOair) |
Popular in | July |
Cheapest in | January |
Average price | $500 |
Good round-trip deal | $611 or less |
Good one-way deal | $392 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Seattle to Ontario that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated June 10, 2026.
Use the filters below to find and compare flights from Seattle to Ontario that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
SeattleToronto
SEA - YKF
SEAYKF
Seattle/Tacoma Intl
Fri 8/14
7:35 pm-7:50 pm
1 stop21h 15m
Toronto Region of Waterloo Intl
Mon 8/17
8:40 pm-9:40 am
1 stop16h 00m
$421
SeattleMontreal
SEA - YUL
SEAYUL
Seattle/Tacoma Intl
Sun 10/4
10:30 am-12:25 am
2 stops10h 55m
Montreal Pierre Elliott Trudeau Intl
Sat 10/10
6:45 am-6:45 pm
2 stops15h 00m
$450
SeattleMontreal
SEA - YUL
SEAYUL
Seattle/Tacoma Intl
Thu 8/27
7:35 pm-7:05 am
1 stop8h 30m
Montreal Pierre Elliott Trudeau Intl
Sun 8/30
8:00 pm-6:45 pm
1 stop25h 45m
$453
SeattleToronto
SEA - YKF
SEAYKF
Seattle/Tacoma Intl
Thu 7/9
7:35 pm-7:50 pm
1 stop21h 15m
Toronto Region of Waterloo Intl
Tue 7/14
8:40 pm-9:40 am
1 stop16h 00m
$456
SeattleToronto
SEA - YKF
SEAYKF
Seattle/Tacoma Intl
Thu 7/23
7:00 am-7:50 pm
1 stop9h 50m
Toronto Region of Waterloo Intl
Tue 7/28
8:40 pm-9:00 pm
1 stop27h 20m
$458
SeattleToronto
SEA - YYZ
SEAYYZ
Seattle/Tacoma Intl
Thu 9/17
8:00 am-3:50 pm
Nonstop4h 50m
Toronto Pearson Intl
Sun 9/20
7:30 am-2:28 pm
1 stop9h 58m
$465
SeattleOttawa
SEA - YOW
SEAYOW
Seattle/Tacoma Intl
Tue 7/7
7:35 pm-7:20 pm
1 stop20h 45m
Ottawa
Tue 7/14
6:55 am-6:45 pm
2 stops14h 50m
$465
SeattleHamilton
SEA - YHM
SEAYHM
Seattle/Tacoma Intl
Fri 8/21
7:00 am-5:15 pm
1 stop7h 15m
Hamilton
Mon 8/24
6:10 pm-9:40 am
1 stop18h 30m
$467
SeattleMontreal
SEA - YUL
SEAYUL
Seattle/Tacoma Intl
Wed 9/23
9:10 am-11:57 pm
1 stop11h 47m
Montreal Pierre Elliott Trudeau Intl
Sat 9/26
7:00 am-12:58 pm
1 stop8h 58m
$473
SeattleMontreal
SEA - YUL
SEAYUL
Seattle/Tacoma Intl
Wed 9/23
9:10 am-11:57 pm
1 stop11h 47m
Montreal Pierre Elliott Trudeau Intl
Wed 9/30
5:10 pm-10:02 pm
1 stop7h 52m
$473
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Seattle to Ontario
Have a flexible travel schedule? Discover the best time to fly to Ontario from Seattle with our price prediction graph.
SEA-YKF
SEA-YYZ
SEA-YUL
SEA-YXU
SEA-YTZ
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 Ontario
SEA-CAON
SEA-YKF
SEA-YYZ
SEA-YUL
SEA-YXU
What is the cheapest month to book a flight from Seattle to Region of Ontario?
Currently, November is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of $88). Flying from Seattle to Region of Ontario in May is currently the most expensive (average of $159). 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 ON?
Find hourly flight availability from Seattle to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 10, 2026.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Seattle to Region of Ontario as you normally would.
Weekly flight availability from Seattle to Region of Ontario
Explore weekly flight availability from Seattle to Ontario. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 10, 2026.
The most flights from SEA to CAON are scheduled on a Monday (5 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (2 on average).
How much does it cost to fly round-trip from Seattle to Region of Ontario?
How far ahead should I book a flight from Seattle to Region of Ontario?
The price you pay for your flight from Seattle to Region of Ontario may vary depending on when you book. For the best chance of a lower fare, look to book 64 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
Reviews of airlines servicing Ontario
Get insights into the airlines that provide service to Ontario. 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 Ontario. Reviews last updated June 10, 2026.
Read through reviews of airlines operating flights from Seattle to Ontario, such as Alaska Airlines,Delta, andUnited Airlines. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Comfort
7.8
Overall
7.9
Boarding
8.1
Entertainment
7.0
Food
7.0
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Overall
7.9
Boarding
8.1
Entertainment
7.0
Food
7.0
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Overall
7.9
Boarding
8.1
Entertainment
7.0
Food
7.0
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Overall
7.9
Boarding
8.1
Entertainment
7.0
Food
7.0
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Overall
7.9
Boarding
8.1
Entertainment
7.0
Food
7.0
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Comfort
7.8
Overall
7.9
Boarding
8.1
Entertainment
7.0
Food
7.0
Crew
8.5
Reviews
1 / 20
4.0
OkayAnonymous,Jun 2026
SEA - RNO
Related info for your journey
Find useful and relevant information for your journey from Seattle to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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 Seattle to Ontario
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Ontario by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Seattle to Ontario by cabin class
Find flights from Seattle to Ontario, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Seattle and Ontario flights
Browse other Seattle and Ontario flight options. Last updated on June 10, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Top 5 airlines flying from Seattle to Ontario
Discover the top 5 airlines that operate flights from Seattle to Ontario. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated June 10, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$132 | Average$482 | FlexibilityNo cancel fee | On-time67% | |
| Cheapest$142 | Average$408 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$226 | Average$352 | FlexibilityNo cancel fee | On-time60% | |
| Cheapest$250 | Average$451 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$277 | Average$500 | FlexibilityNo cancel fee | On-time69% |