$126+ Cheap flights from Seattle (SEA) to Ontario
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/21. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — YYZ
Oct 8 — Oct 151
Round-trip
1 adult, Economy
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Find cheap flights from Seattle to Ontario with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
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Cheapest flights from Seattle to 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 September 8, 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 September 8, 2026.
This Trip.com deal was found by Cheapflights users on 9/7. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/107:35 pm -
1 stop8h 30m
Tue 10/136:45 am -
2 stops15h 00m
Deal found 9/7![WestJet logo]()
$316
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/107:35 pm -
1 stop7h 00m
Wed 10/147:20 am -
1 stop14h 25m
Deal found 9/4![WestJet logo]()
$318
This Kiwi.com deal was found by Cheapflights users on 9/6. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/287:35 pm -
1 stop7h 00m
Fri 10/21:20 pm -
1 stop8h 25m
Deal found 9/6![WestJet logo]()
$319
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/197:35 pm -
1 stop7h 00m
Wed 9/231:20 pm -
1 stop8h 25m
Deal found 9/3![WestJet logo]()
$322
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/257:35 pm -
1 stop8h 30m
Sat 10/36:45 am -
2 stops15h 00m
Deal found 9/4![WestJet logo]()
$324
This Trip.com deal was found by Cheapflights users on 9/5. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/117:35 pm -
1 stop7h 00m
Tue 10/136:55 am -
2 stops14h 50m
Deal found 9/5![WestJet logo]()
$326
This Trip.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1710:30 am -
2 stops10h 50m
Wed 9/231:20 pm -
1 stop8h 25m
Deal found 9/4![WestJet logo]()
$328
This Kiwi.com deal was found by Cheapflights users on 9/6. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/257:35 pm -
1 stop7h 00m
Thu 10/11:20 pm -
1 stop8h 25m
Deal found 9/6![WestJet logo]()
$330
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/37:35 pm -
1 stop8h 30m
Sat 10/176:45 am -
2 stops15h 00m
Deal found 9/5![WestJet logo]()
$331
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/267:35 pm -
1 stop8h 30m
Tue 10/66:45 am -
2 stops15h 00m
Deal found 9/4![WestJet logo]()
$332
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/147:35 pm -
1 stop8h 30m
Wed 10/216:45 am -
2 stops15h 00m
Deal found 9/3![WestJet logo]()
$333
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/67:35 pm -
1 stop8h 30m
Mon 10/196:45 am -
2 stops15h 00m
Deal found 9/5![WestJet logo]()
$334
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 September 8, 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 September 8, 2026.
This Trip.com deal was found by Cheapflights users on 9/5. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/117:35 pm -
1 stop7h 00m
Tue 10/136:55 am -
2 stops14h 50m
Deal found 9/5![WestJet logo]()
$326
This Kiwi.com deal was found by Cheapflights users on 9/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/147:35 pm -
1 stop7h 00m
Wed 10/2110:00 am -
2 stops11h 45m
Deal found 9/7![Multiple Airlines logo]()
$347
This United Airlines deal was found by Cheapflights users on 9/5. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2011:13 pm -
1 stop15h 17m
Tue 10/273:00 pm -
1 stop9h 39m
Deal found 9/5![United Airlines logo]()
$486
This Delta deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/89:40 am -
2 stops11h 03m
Thu 1/712:45 pm -
2 stops11h 05m
Deal found 9/4![Delta logo]()
$499
This Alaska Airlines deal was found by Cheapflights users on 9/6. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/108:19 am -
Nonstop4h 46m
Thu 11/125:15 pm -
Nonstop5h 30m
Deal found 9/6![Alaska Airlines logo]()
$519
This Air Canada deal was found by Cheapflights users on 9/6. 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.
Fri 10/167:15 pm -
2 stops12h 40m
Tue 10/204:30 pm -
2 stops20h 35m
Deal found 9/6![Air Canada logo]()
$559
This Trip.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/187:35 pm -
1 stop7h 00m
Sun 10/256:10 am -
1 stop11h 30m
Deal found 9/3![WestJet logo]()
$336
This Flightnetwork deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/187:35 pm -
1 stop7h 00m
Sun 10/257:50 am -
2 stops13h 32m
Deal found 9/3![Multiple Airlines logo]()
$366
This Trip.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/17:35 pm -
1 stop8h 30m
Thu 10/86:45 am -
2 stops15h 00m
Deal found 9/3![WestJet logo]()
$351
This Mytrip deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/177:15 pm -
3 stops16h 40m
Tue 10/277:50 am -
2 stops13h 32m
Deal found 9/4![Multiple Airlines logo]()
$387
This Justfly.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/110:30 am -
2 stops10h 50m
Mon 10/56:15 pm -
2 stops27h 30m
Deal found 9/3![WestJet logo]()
$370
This Trip.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/187:35 pm -
1 stop16h 25m
Tue 9/298:40 pm -
1 stop25h 05m
Deal found 9/3![Multiple Airlines logo]()
$410
This United Airlines deal was found by Cheapflights users on 9/6. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/235:20 pm -
1 stop11h 56m
Sat 10/36:10 am -
3 stops18h 05m
Deal found 9/6![United Airlines logo]()
$497
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/197:35 pm -
2 stops13h 55m
Mon 10/266:10 am -
1 stop11h 30m
Deal found 9/3![WestJet logo]()
$382
This Delta deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/139:40 am -
2 stops11h 03m
Sun 1/1012:45 pm -
2 stops22h 03m
Deal found 9/4![Delta logo]()
$509
This United Airlines deal was found by Cheapflights users on 9/7. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/15:07 pm -
1 stop14h 33m
Mon 10/56:35 pm -
1 stop9h 40m
Deal found 9/7![United Airlines logo]()
$506
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/197:35 pm -
1 stop14h 20m
Mon 10/266:10 am -
1 stop11h 30m
Deal found 9/3![Multiple Airlines logo]()
$421
This Delta deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2612:00 pm -
1 stop8h 44m
Mon 10/512:48 pm -
1 stop12h 17m
Deal found 9/4![Delta logo]()
$516
This FlightHub deal was found by Cheapflights users on 9/8. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/157:35 pm -
1 stop21h 15m
Sun 10/188:40 pm -
1 stop16h 00m
Deal found 9/8![WestJet logo]()
$392
This Alaska Airlines deal was found by Cheapflights users on 9/5. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 1/158:29 am -
Nonstop4h 36m
Sun 1/245:15 pm -
Nonstop5h 27m
Deal found 9/5![Alaska Airlines logo]()
$579
This United Airlines deal was found by Cheapflights users on 9/5. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/307:00 am -
1 stop7h 30m
Mon 10/196:35 pm -
1 stop9h 40m
Deal found 9/5![United Airlines logo]()
$506
This Delta deal was found by Cheapflights users on 9/7. 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.
Fri 10/236:55 pm -
2 stops10h 54m
Fri 10/306:30 am -
2 stops10h 09m
Deal found 9/7![Delta logo]()
$520
This Mytrip deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/287:35 pm -
1 stop18h 40m
Thu 10/16:05 am -
3 stops15h 40m
Deal found 9/4![Multiple Airlines logo]()
$440
This Alaska Airlines deal was found by Cheapflights users on 9/5. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/307:52 am -
Nonstop4h 53m
Thu 10/84:55 pm -
Nonstop5h 31m
Deal found 9/5![Alaska Airlines logo]()
$586
This FlightHub deal was found by Cheapflights users on 9/6. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/87:35 pm -
1 stop18h 40m
Mon 10/126:10 pm -
1 stop27h 35m
Deal found 9/6![WestJet logo]()
$401
This Air Canada deal was found by Cheapflights users on 9/6. 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.
Tue 10/207:55 am -
1 stop8h 45m
Sat 10/249:05 am -
2 stops12h 27m
Deal found 9/6![Air Canada logo]()
$683
This United Airlines deal was found by Cheapflights users on 9/6. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/277:00 am -
1 stop7h 30m
Thu 10/86:35 pm -
1 stop9h 40m
Deal found 9/6![United Airlines logo]()
$525
This Gotogate deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/1410:30 am -
2 stops10h 55m
Wed 10/216:45 am -
2 stops15h 00m
Deal found 9/3![WestJet logo]()
$405
This Delta deal was found by Cheapflights users on 9/7. 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.
Fri 10/28:59 pm -
2 stops10h 24m
Tue 10/66:00 am -
2 stops10h 39m
Deal found 9/7![Delta logo]()
$542
This Mytrip deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/77:35 pm -
1 stop16h 25m
Sun 10/116:05 am -
1 stop15h 40m
Deal found 9/3![Multiple Airlines logo]()
$450
Last-minute flights from Seattle to OntarioDiscover last-minute flight deals from Seattle to Ontario. Data last updated September 8, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Ontario. Data last updated September 8, 2026 and is based on user searches.
This Trip.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1710:30 am -
2 stops10h 50m
Wed 9/231:20 pm -
1 stop8h 25m
Deal found 9/4![WestJet logo]()
$328
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/197:35 pm -
1 stop7h 00m
Wed 9/231:20 pm -
1 stop8h 25m
Deal found 9/3![WestJet logo]()
$322
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/257:35 pm -
1 stop8h 30m
Sat 10/36:45 am -
2 stops15h 00m
Deal found 9/4![WestJet logo]()
$324
This Kiwi.com deal was found by Cheapflights users on 9/6. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/257:35 pm -
1 stop7h 00m
Thu 10/11:20 pm -
1 stop8h 25m
Deal found 9/6![WestJet logo]()
$330
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/267:35 pm -
1 stop8h 30m
Wed 10/76:45 am -
2 stops15h 00m
Deal found 9/4![WestJet logo]()
$332
This Kiwi.com deal was found by Cheapflights users on 9/6. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/287:35 pm -
1 stop7h 00m
Fri 10/21:20 pm -
1 stop8h 25m
Deal found 9/6![WestJet logo]()
$319
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/37:35 pm -
1 stop8h 30m
Wed 10/146:45 am -
2 stops15h 00m
Deal found 9/5![WestJet logo]()
$331
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/67:35 pm -
1 stop8h 30m
Wed 10/146:45 am -
2 stops15h 00m
Deal found 9/5![WestJet logo]()
$334
This Trip.com deal was found by Cheapflights users on 9/7. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/107:35 pm -
1 stop8h 30m
Tue 10/136:45 am -
2 stops15h 00m
Deal found 9/7![WestJet logo]()
$316
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/107:35 pm -
1 stop7h 00m
Wed 10/147:20 am -
1 stop14h 25m
Deal found 9/4![WestJet logo]()
$318
This Trip.com deal was found by Cheapflights users on 9/5. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/117:35 pm -
1 stop7h 00m
Tue 10/136:55 am -
2 stops14h 50m
Deal found 9/5![WestJet logo]()
$326
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/147:35 pm -
1 stop8h 30m
Wed 10/216:45 am -
2 stops15h 00m
Deal found 9/3![WestJet logo]()
$333
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 September 8, 2026.
Search for one-way flight options from Seattle to Ontario. Find affordable one-way fares based on user searches. Data last updated September 8, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/217:35 pm -
1 stop7h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/5![WestJet logo]()
$126
This Kiwi.com deal was found by Cheapflights users on 9/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/37:35 pm -
1 stop7h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/7![WestJet logo]()
$131
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/117:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/5![WestJet logo]()
$137
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/37:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/3![WestJet logo]()
$142
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/137:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/5![WestJet logo]()
$143
This Kiwi.com deal was found by Cheapflights users on 9/5. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/147:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/5![WestJet logo]()
$146
This Kiwi.com deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/157:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/4![WestJet logo]()
$147
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/67:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/3![WestJet logo]()
$149
This FlightHub deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/257:35 pm -
1 stop8h 30m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/4![WestJet logo]()
$156
This FlightHub deal was found by Cheapflights users on 9/4. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/157:35 pm -
1 stop7h 00m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/4![WestJet logo]()
$156
This Kiwi.com deal was found by Cheapflights users on 9/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/710:30 am -
2 stops10h 55m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/3![WestJet logo]()
$158
This Trip.com deal was found by Cheapflights users on 9/6. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/1810:30 am -
2 stops10h 55m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/6![WestJet logo]()
$159
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 September 8, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $316 (Trip.com) |
One-way from | $126 (Kiwi.com) |
Popular in | July |
Cheapest in | January |
Average price | $580 |
Good round-trip deal | $557 or less |
Good one-way deal | $309 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 7,457,451 searches. Data last updated September 8, 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
SeattleMontreal
SEA Seattle/Tacoma Intl - YUL Montreal Pierre Elliott Trudeau Intl
SEAYUL
Seattle/Tacoma Intl
Sun 10/11
7:35 pm-7:05 am
1 stop8h 30m
Montreal Pierre Elliott Trudeau Intl
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$137
SeattleMontreal
SEA Seattle/Tacoma Intl - YUL Montreal Pierre Elliott Trudeau Intl
SEAYUL
Seattle/Tacoma Intl
Sat 10/3
7:35 pm-7:05 am
1 stop8h 30m
Montreal Pierre Elliott Trudeau Intl
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$142
SeattleOttawa
SEA Seattle/Tacoma Intl - YOW Ottawa
SEAYOW
Seattle/Tacoma Intl
Tue 9/15
7:35 pm-5:35 am
1 stop7h 00m
Ottawa
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$156
SeattleOttawa
SEA Seattle/Tacoma Intl - YOW Ottawa
SEAYOW
Seattle/Tacoma Intl
Sat 10/10
10:30 am-12:20 am
2 stops10h 50m
Ottawa
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$170
SeattleOttawa
SEA Seattle/Tacoma Intl - YOW Ottawa
SEAYOW
Seattle/Tacoma Intl
Mon 10/5
9:36 pm-5:15 pm
2 stops16h 39m
Ottawa
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$174
SeattleHamilton
SEA Seattle/Tacoma Intl - YHM Hamilton
SEAYHM
Seattle/Tacoma Intl
Tue 9/15
10:30 am-5:15 pm
1 stop27h 45m
Hamilton
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$181
SeattleToronto
SEA Seattle/Tacoma Intl - YKF Toronto Region of Waterloo Intl
SEAYKF
Seattle/Tacoma Intl
Fri 9/18
7:35 pm-7:50 pm
1 stop21h 15m
Toronto Region of Waterloo Intl
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$183
SeattleToronto
SEA Seattle/Tacoma Intl - YKF Toronto Region of Waterloo Intl
SEAYKF
Seattle/Tacoma Intl
Tue 9/29
7:35 pm-7:50 pm
1 stop21h 15m
Toronto Region of Waterloo Intl
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$184
SeattleOttawa
SEA Seattle/Tacoma Intl - YOW Ottawa
SEAYOW
Seattle/Tacoma Intl
Sat 10/10
10:30 am-5:58 pm
1 stop28h 28m
Ottawa
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$185
SeattleHamilton
SEA Seattle/Tacoma Intl - YHM Hamilton
SEAYHM
Seattle/Tacoma Intl
Sat 9/19
7:35 pm-5:15 pm
1 stop18h 40m
Hamilton
Wed 12/31
12:00 am-9:00 pm
Nonstop0h 00m
$186
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-YOW
SEA-YUL
SEA-YYZ
SEA-YHM
SEA-YKF
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-YOW
SEA-YUL
SEA-YYZ
SEA-YHM
What is the cheapest month to book a flight from Seattle to Region of Ontario?
Currently, January is the cheapest month in which you can book a flight from Seattle to Region of Ontario (average of $274). Flying from Seattle to Region of Ontario in July is currently the most expensive (average of $606). 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 September 8, 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.
How much does it cost to fly round-trip from Seattle to Region of Ontario?
Airfare is below average for this route at the moment.
Seattle to Region of Ontario flights typically cost between $425 and $690 in October.The cheapest round-trip price found within the last 5 days was $369 on WestJet (Oct 23-Oct 27).
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 59 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 September 8, 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.
Entertainment
7.0
Comfort
7.8
Food
7.0
Crew
8.5
Overall
7.9
Boarding
8.1
Reviews
1 / 20
6.0
GoodAnonymous,Jul 2026
SEA - LHR
Entertainment
7.0
Comfort
7.8
Food
7.0
Crew
8.5
Overall
7.9
Boarding
8.1
Reviews
1 / 20
6.0
GoodAnonymous,Jul 2026
SEA - LHR
Entertainment
7.0
Comfort
7.8
Food
7.0
Crew
8.5
Overall
7.9
Boarding
8.1
Reviews
1 / 20
6.0
GoodAnonymous,Jul 2026
SEA - LHR
Entertainment
7.0
Comfort
7.8
Food
7.0
Crew
8.5
Overall
7.9
Boarding
8.1
Reviews
1 / 20
6.0
GoodAnonymous,Jul 2026
SEA - LHR
Entertainment
7.0
Comfort
7.8
Food
7.0
Crew
8.5
Overall
7.9
Boarding
8.1
Reviews
1 / 20
6.0
GoodAnonymous,Jul 2026
SEA - LHR
Entertainment
7.0
Comfort
7.8
Food
7.0
Crew
8.5
Overall
7.9
Boarding
8.1
Reviews
1 / 20
6.0
GoodAnonymous,Jul 2026
SEA - LHR
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.
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Alternative routes for Seattle to Ontario
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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 September 8, 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 7,457,451 searches. Data last updated September 8, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$132 | Average$379 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$132 | Average$522 | FlexibilityNo cancel fee | On-time67% | |
| Cheapest$228 | Average$383 | FlexibilityNo cancel fee | On-time60% | |
| Cheapest$250 | Average$467 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$277 | Average$567 | FlexibilityNo cancel fee | On-time69% |