$71+ Cheap flights from Seattle to Ontario (SEA - ONT)
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 9/26. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ONT
Oct 23 — Oct 301
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
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Ontario are usually found in October or August, booked 60 days in advance, depart on a Thursday or Wednesday and return on a Friday
Cheap flight deals from Seattle to Ontario
Cheapest
Best
Last-minute
One-way
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 23, 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 23, 2026.
This deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Mon 9/285:44 pm -
Nonstop2h 56m
Deal found 9/18![Frontier logo]()
$136
This FlightHub deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Wed 9/235:44 pm -
Nonstop2h 56m
Deal found 9/22![Frontier logo]()
$148
This Kiwi.com deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Sat 9/265:34 pm -
Nonstop2h 56m
Deal found 9/20![Frontier logo]()
$160
This Mytrip deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” 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 10/314:27 pm -
1 stop7h 24m
Sat 11/76:25 am -
1 stop8h 47m
Deal found 9/18![Frontier logo]()
$171
This Super.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/211:00 am -
Nonstop2h 52m
Sat 12/56:39 am -
Nonstop3h 06m
Deal found 9/19![Frontier logo]()
$174
This Super.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2610:53 am -
Nonstop2h 52m
Mon 9/285:44 pm -
Nonstop2h 56m
Deal found 9/22![Frontier logo]()
$182
This Cheapflightsfares deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Thu 9/245:44 pm -
Nonstop2h 56m
Deal found 9/21![Frontier logo]()
$183
This Frontier deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/211:00 am -
Nonstop2h 52m
Mon 12/76:39 am -
Nonstop3h 06m
Deal found 9/22![Frontier logo]()
$188
This Mytrip deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” 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.
Thu 10/2210:03 am -
Nonstop2h 50m
Wed 10/286:25 am -
1 stop8h 47m
Deal found 9/18![Frontier logo]()
$190
This Super.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Sat 10/35:34 pm -
Nonstop2h 56m
Deal found 9/22![Frontier logo]()
$191
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 23, 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 23, 2026.
This Delta deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 1/2711:15 am -
Nonstop2h 42m
Sun 1/317:00 am -
Nonstop3h 05m
Deal found 9/22![Delta logo]()
$257
This Alaska Airlines deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/103:41 pm -
Nonstop2h 36m
Sun 11/156:00 am -
Nonstop2h 51m
Deal found 9/20![Alaska Airlines logo]()
$282
This United Airlines deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/201:16 pm -
1 stop6h 59m
Sun 11/221:35 pm -
1 stop7h 12m
Deal found 9/22![United Airlines logo]()
$342
This Southwest deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/245:15 am -
1 stop5h 15m
Wed 12/304:40 pm -
1 stop7h 25m
Deal found 9/21![Southwest logo]()
$365
This Delta deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/148:11 pm -
Nonstop2h 49m
Sun 11/157:00 am -
Nonstop3h 01m
Deal found 9/18![Delta logo]()
$282
This Alaska Airlines deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2910:58 am -
1 stop6h 07m
Sun 11/16:00 am -
Nonstop2h 51m
Deal found 9/18![Alaska Airlines logo]()
$307
This Delta deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/218:25 am -
Nonstop2h 51m
Mon 10/266:00 pm -
Nonstop2h 59m
Deal found 9/21![Delta logo]()
$282
This Delta deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/317:56 pm -
Nonstop2h 47m
Mon 11/26:00 pm -
Nonstop2h 59m
Deal found 9/21![Delta logo]()
$283
This Alaska Airlines deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 1/113:44 pm -
1 stop4h 18m
Fri 1/157:10 am -
1 stop5h 47m
Deal found 9/18![Alaska Airlines logo]()
$317
This Alaska Airlines deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 1/2712:35 pm -
1 stop4h 42m
Sun 1/317:10 am -
1 stop4h 30m
Deal found 9/22![Alaska Airlines logo]()
$332
This Delta deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/108:25 am -
Nonstop2h 52m
Sun 11/151:15 pm -
1 stop5h 26m
Deal found 9/20![Delta logo]()
$313
Last-minute flights from Seattle to OntarioDiscover last-minute flight deals from Seattle to Ontario. Data last updated September 23, 2026 and is based on user searches.
Discover last-minute flight deals from Seattle to Ontario. Data last updated September 23, 2026 and is based on user searches.
This deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Mon 9/285:44 pm -
Nonstop2h 56m
Deal found 9/18![Frontier logo]()
$136
This Cheapflightsfares deal was found by Cheapflights users on 9/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Wed 9/235:44 pm -
Nonstop2h 56m
Deal found 9/23![Frontier logo]()
$142
This Kiwi.com deal was found by Cheapflights users on 9/20. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Sat 9/265:34 pm -
Nonstop2h 56m
Deal found 9/20![Frontier logo]()
$160
This Cheapflightsfares deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Thu 9/245:44 pm -
Nonstop2h 56m
Deal found 9/21![Frontier logo]()
$183
This Super.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/2310:53 am -
Nonstop2h 52m
Sat 10/35:34 pm -
Nonstop2h 56m
Deal found 9/22![Frontier logo]()
$191
This Super.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2610:53 am -
Nonstop2h 52m
Mon 9/285:44 pm -
Nonstop2h 56m
Deal found 9/22![Frontier logo]()
$182
This Mytrip deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” 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.
Thu 10/2210:03 am -
Nonstop2h 50m
Wed 10/286:25 am -
1 stop8h 47m
Deal found 9/18![Frontier logo]()
$190
This Cheapflightsfares deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2210:03 am -
Nonstop2h 50m
Tue 10/2711:52 am -
1 stop27h 20m
Deal found 9/18![Frontier logo]()
$192
This Mytrip deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” 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 10/314:27 pm -
1 stop7h 24m
Sat 11/76:25 am -
1 stop8h 47m
Deal found 9/18![Frontier logo]()
$171
This Mytrip deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” 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 10/314:27 pm -
1 stop7h 24m
Mon 11/25:06 pm -
Nonstop3h 02m
Deal found 9/18![Frontier logo]()
$193
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 23, 2026.
Search for one-way flight options from Seattle to Ontario. Find affordable one-way fares based on user searches. Data last updated September 23, 2026.
This Super.com deal was found by Cheapflights users on 9/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2610:53 am -
Nonstop2h 52m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/21![Frontier logo]()
$71
This Super.com deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/244:27 pm -
1 stop7h 23m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/18![Frontier logo]()
$81
This Super.com deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/184:27 pm -
1 stop18h 08m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/18![Frontier logo]()
$85
This Super.com deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/511:00 am -
Nonstop2h 46m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/18![Frontier logo]()
$87
This Super.com deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/3010:50 am -
Nonstop2h 48m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Frontier logo]()
$98
This Cheapflightsfares deal was found by Cheapflights users on 9/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/2910:50 am -
Nonstop2h 48m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/22![Frontier logo]()
$99
This Cheapflightsfares deal was found by Cheapflights users on 9/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/1910:53 am -
Nonstop2h 50m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/18![Frontier logo]()
$102
This Super.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/2610:53 am -
Nonstop2h 50m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/19![Frontier logo]()
$103
This Booking.com deal was found by Cheapflights users on 9/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/2310:53 am -
Nonstop2h 50m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/19![Frontier logo]()
$105
Find flight deals from Seattle to Ontario
Discover tips and strategies to find the most affordable flight options for your journey from Seattle (SEA) to Ontario (ONT). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 23, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $171 (Mytrip) |
One-way from | $71 (Super.com) |
Popular in | February |
Cheapest in | October |
Average price | $268 |
Good round-trip deal | $174 or less |
Good one-way deal | $94 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 23, 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
Quickest round-trip
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Thu 10/29
9:06 pm-11:42 pm
Nonstop2h 36m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$179
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Fri 11/13
7:55 am-3:20 pm
2 stops7h 25m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$194
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Fri 12/18
10:00 am-5:15 pm
1 stop7h 15m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$199
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Fri 11/20
7:55 am-3:20 pm
2 stops7h 25m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$204
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Fri 12/25
5:40 am-2:30 pm
2 stops8h 50m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$204
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Thu 10/29
2:10 pm-9:25 pm
2 stops7h 15m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$204
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Wed 3/17
2:35 pm-5:17 pm
Nonstop2h 42m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$219
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Sat 3/20
12:00 pm-2:47 pm
Nonstop2h 47m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$219
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Thu 12/24
8:31 am-11:10 am
Nonstop2h 39m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$219
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Thu 11/12
7:00 am-12:29 pm
1 stop5h 29m
Ontario
Wed 12/31
12:00 am-12:00 am
Nonstop0h 00m
$224
Showing 1-10 of 22 resultsSorted by cheapest first
Compare providers for flights from Seattle to Ontario
Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Seattle to Ontario in September.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*1 star | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars | |
| Price Accuracy2 stars | Trust Score*3 stars | |
| Price Accuracy- | Trust Score*3 stars | |
| Price Accuracy1 star | Trust Score*3 stars |
- Most accurate provider: When it comes to deals on Seattle-Ontario flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Seattle-Ontario flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Seattle-Ontario flight searches over the past month and is updated monthly.
- Most trusted provider: When it comes to deals on Seattle-Ontario flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Seattle-Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.
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-ONT
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
Prices
Airlines
How far ahead should I book a flight from Seattle to Ontario?
The best time to book flights from Seattle to Ontario is 59 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.
What is the cheapest month to book a flight from Seattle to Ontario?
Currently, October is the cheapest month in which you can book a flight from Seattle to Ontario (average of $232). Flying from Seattle to Ontario in February is currently the most expensive (average of $374). 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 ONT?
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 23, 2026.
A simple way to save on the total cost of your ticket is to fly from Seattle to Ontario in the morning. If you’re flexible enough to do this you can expect to save up to 17% on your trip compared to booking a flight in the afternoon.
What is the cheapest day to fly from Seattle to Ontario?
Use this chart to determine the cheapest time to fly round-trip from Seattle to Ontario. Price data was last updated on September 19, 2026.
Travelers seeking maximum savings on their Seattle to Ontario flight should consider departing on Monday at noon when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.
The best insider tips for Seattle to Ontario flights
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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 23, 2026.
See what other customers who have flown with Southwest,Alaska Airlines, andDelta from Seattle to Ontario have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Boarding
8.1
Crew
8.6
Overall
8.0
Entertainment
7.5
Food
7.0
Comfort
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Boarding
8.1
Crew
8.6
Overall
8.0
Entertainment
7.5
Food
7.0
Comfort
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Boarding
8.1
Crew
8.6
Overall
8.0
Entertainment
7.5
Food
7.0
Comfort
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Boarding
8.1
Crew
8.6
Overall
8.0
Entertainment
7.5
Food
7.0
Comfort
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Boarding
8.1
Crew
8.6
Overall
8.0
Entertainment
7.5
Food
7.0
Comfort
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
Boarding
8.1
Crew
8.6
Overall
8.0
Entertainment
7.5
Food
7.0
Comfort
8.0
Reviews
1 / 20
10.0
ExcellentWalter,May 2026
LAS - BUR
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.
Other flights to Ontario
Explore flights to Ontario departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on September 23, 2026.
Seattle and Ontario flights
Browse other Seattle and Ontario flight options. Last updated on September 23, 2026.
Other flights from Seattle
Browse through other flights departing from Seattle. Flights are based on user searches made on Cheapflights and were last updated on September 23, 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 23, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$88 | Average$227 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$108 | Average$299 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$138 | Average$320 | FlexibilityNo cancel fee | On-time75% | |
| Cheapest$150 | Average$291 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$163 | Average$387 | FlexibilityNo cancel fee | On-time85% |