This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/11. Fares are subject to change and may not be available on all flights or dates of travel.
SEA — ONT
19 Nov — 26 Nov1
Round-trip
1 adult
Economy
Round-trip
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Seattle/Tacoma Intl to Ontario are usually found in August or May, booked 74 days in advance, depart on a Friday or Thursday and return on a Monday
Cheap flight deals from Seattle to Ontario
Enter your travel dates to find the best prices.
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Direct
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One-way
Cheapest flights from Seattle to Ontario
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 20 October 2026.
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 231
Wed 11/114:27 p.m. -
1 stop7h 24m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 253
Fri 13/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 259
Tue 24/1110:18 a.m. -
Nonstop2h 48m
Fri 27/116:00 a.m. -
Nonstop3h 03m
Deal found 18/10C$ 262
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Sat 14/116:30 a.m. -
1 stop8h 42m
Deal found 19/10C$ 276
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Wed 18/116:30 a.m. -
1 stop8h 42m
Deal found 15/10C$ 288
Mon 9/114:27 p.m. -
1 stop7h 24m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 300
Wed 11/114:27 p.m. -
1 stop7h 24m
Wed 18/116:30 a.m. -
1 stop8h 42m
Deal found 15/10C$ 311
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Fri 20/116:00 a.m. -
Nonstop3h 03m
Deal found 15/10C$ 315
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Wed 11/116:30 a.m. -
1 stop8h 42m
Deal found 18/10C$ 316
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Mon 16/116:30 a.m. -
1 stop8h 42m
Deal found 15/10C$ 335
Best flights from Seattle to Ontario
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 20 October 2026.
Sat 14/118:11 p.m. -
Nonstop2h 49m
Tue 17/115:56 p.m. -
Nonstop3h 01m
Deal found 15/10C$ 347
Sat 19/129:23 p.m. -
Nonstop2h 36m
Wed 23/126:00 a.m. -
Nonstop2h 52m
Deal found 17/10C$ 404
Thu 10/128:25 a.m. -
Nonstop2h 52m
Sun 13/127:00 a.m. -
Nonstop3h 05m
Deal found 20/10C$ 368
Sat 14/118:11 p.m. -
Nonstop2h 49m
Thu 19/115:56 p.m. -
Nonstop3h 01m
Deal found 15/10C$ 376
Wed 23/129:23 p.m. -
Nonstop2h 36m
Sat 26/126:00 a.m. -
Nonstop2h 52m
Deal found 19/10C$ 425
Sat 14/118:11 p.m. -
Nonstop2h 49m
Mon 16/115:56 p.m. -
Nonstop3h 01m
Deal found 15/10C$ 376
Sat 19/129:23 p.m. -
Nonstop2h 36m
Sat 26/126:00 a.m. -
Nonstop2h 52m
Deal found 20/10C$ 460
Sat 14/118:11 p.m. -
Nonstop2h 49m
Sun 15/117:00 a.m. -
Nonstop3h 01m
Deal found 15/10C$ 383
Sun 20/129:23 p.m. -
Nonstop2h 36m
Sun 27/126:00 a.m. -
Nonstop2h 52m
Deal found 18/10C$ 481
Fri 5/27:55 p.m. -
Nonstop2h 48m
Sun 7/27:00 a.m. -
Nonstop3h 05m
Deal found 16/10C$ 418
Thu 18/28:27 a.m. -
Nonstop2h 42m
Sun 21/26:22 p.m. -
1 stop14h 58m
Deal found 20/10C$ 496
Tue 22/127:50 p.m. -
Nonstop2h 47m
Mon 28/125:38 p.m. -
Nonstop3h 05m
Deal found 19/10C$ 481
Direct flights from Seattle to Ontario
Explore direct flight options from Seattle to Ontario based on user searches, and compare prices and availability for your desired travel dates. Data last updated 20 October 2026.
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 231
Fri 13/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 259
Tue 24/1110:18 a.m. -
Nonstop2h 48m
Fri 27/116:00 a.m. -
Nonstop3h 03m
Deal found 18/10C$ 262
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Fri 20/116:00 a.m. -
Nonstop3h 03m
Deal found 15/10C$ 315
Mon 9/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 343
Tue 22/129:23 p.m. -
Nonstop2h 36m
Wed 30/126:00 a.m. -
Nonstop2h 52m
Deal found 20/10C$ 347
Sun 20/129:23 p.m. -
Nonstop2h 36m
Tue 29/128:59 p.m. -
Nonstop2h 52m
Deal found 20/10C$ 359
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Sun 15/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 364
Wed 23/129:23 p.m. -
Nonstop2h 36m
Tue 29/128:59 p.m. -
Nonstop2h 52m
Deal found 16/10C$ 366
Sun 20/129:23 p.m. -
Nonstop2h 36m
Fri 1/16:00 a.m. -
Nonstop2h 52m
Deal found 20/10C$ 370
Sun 20/127:50 p.m. -
Nonstop2h 47m
Wed 30/127:00 a.m. -
Nonstop3h 05m
Deal found 20/10C$ 376
Last-minute flights from Seattle to Ontario
Discover last-minute flight deals from Seattle to Ontario. Data last updated 20 October 2026 and is based on user searches.
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 231
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Sat 14/116:30 a.m. -
1 stop8h 42m
Deal found 19/10C$ 276
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Wed 18/116:30 a.m. -
1 stop8h 42m
Deal found 15/10C$ 288
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Fri 20/116:00 a.m. -
Nonstop3h 03m
Deal found 15/10C$ 315
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Wed 11/116:30 a.m. -
1 stop8h 42m
Deal found 18/10C$ 316
Sun 8/1110:50 a.m. -
Nonstop2h 48m
Mon 16/116:30 a.m. -
1 stop8h 42m
Deal found 15/10C$ 335
Mon 9/114:27 p.m. -
1 stop7h 24m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 300
Wed 11/114:27 p.m. -
1 stop7h 24m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 253
Wed 11/114:27 p.m. -
1 stop7h 24m
Wed 18/116:30 a.m. -
1 stop8h 42m
Deal found 15/10C$ 311
Fri 13/1110:50 a.m. -
Nonstop2h 48m
Thu 19/115:06 p.m. -
Nonstop3h 02m
Deal found 15/10C$ 259
Tue 24/1110:18 a.m. -
Nonstop2h 48m
Fri 27/116:00 a.m. -
Nonstop3h 03m
Deal found 18/10C$ 262
One-way flights from Seattle to Ontario
Search for one-way flight options from Seattle to Ontario. Find affordable one-way fares based on user searches. Data last updated 20 October 2026.
Wed 11/114:27 p.m. -
1 stop7h 24m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 15/10C$ 156
Mon 30/119:53 p.m. -
2 stops25h 05m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 18/10C$ 177
Wed 16/127:57 p.m. -
1 stop3h 57m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 19/10C$ 188
Tue 1/128:25 a.m. -
Nonstop2h 52m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 20/10C$ 196
Thu 19/115:15 a.m. -
1 stop5h 15m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 19/10C$ 198
Mon 9/114:27 p.m. -
1 stop7h 24m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 15/10C$ 203
Thu 12/117:55 a.m. -
2 stops7h 25m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 19/10C$ 207
Wed 4/114:27 p.m. -
1 stop7h 24m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 17/10C$ 212
Wed 18/118:34 a.m. -
Nonstop2h 44m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 19/10C$ 217
Sun 15/117:00 a.m. -
1 stop5h 29m
Wed 31/1212:00 a.m. -
Nonstop0h 00m
Deal found 16/10C$ 224
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 20 October 2026.
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 20 October 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
Price
Cheapest round-trip
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Wed 9/12
8:11 p.m.-10:59 p.m.
Nonstop2h 48m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 196
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Wed 3/3
7:55 p.m.-10:39 p.m.
Nonstop2h 44m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 196
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Wed 2/12
8:25 a.m.-11:17 a.m.
Nonstop2h 52m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 196
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Thu 10/12
3:20 p.m.-8:38 p.m.
1 stop5h 18m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 217
Quickest round-trip
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Mon 21/12
9:23 p.m.-11:59 p.m.
Nonstop2h 36m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 245
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Thu 10/12
8:11 p.m.-10:59 p.m.
Nonstop2h 48m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 245
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Sun 13/12
8:11 p.m.-10:59 p.m.
Nonstop2h 48m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 252
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Tue 3/11
4:40 p.m.-9:20 p.m.
1 stop4h 40m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 294
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Wed 4/11
8:34 a.m.-11:18 a.m.
Nonstop2h 44m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 322
SeattleOntario
SEA Seattle/Tacoma Intl - ONT Ontario
SEAONT
Seattle/Tacoma Intl
Tue 10/11
12:31 p.m.-3:13 p.m.
Nonstop2h 42m
Ontario
Wed 31/12
12:00 a.m.-12:00 a.m.
Nonstop0h 00m
C$ 336
Flights are sorted by cheapest round-trip flights first.
Deals found on 20/10
Showing 1-10 of 22 resultsSorted by cheapest first
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3
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?
Booking 73 days in advance of your planned departure date is, on average, the best time to get cheap flights from Seattle to Ontario. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
What is the cheapest month to book a flight from Seattle to Ontario?
Currently, August is the cheapest month in which you can book a flight from Seattle to Ontario (average of C$ 354). Flying from Seattle to Ontario in February is currently the most expensive (average of C$ 523). 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 20 October 2026.
One of the essential ways to save on airfare from Seattle to Ontario is to remain as flexible as possible. Flights that are at noon tend to be the most expensive. A flight in the evening could potentially save you up to 45% on airfare.
How much does it cost to fly round-trip from Seattle to Ontario?
Airfare is below average for this route at the moment.
Seattle to Ontario flights typically cost between C$ 298 and C$ 543 in November.The cheapest round-trip price found within the last 5 days was C$ 231 on Frontier (8 Nov-19 Nov).
Weekly flight availability from Seattle to 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 20 October 2026.
The most flights from SEA to ONT are scheduled on a Monday (19 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (3 on average).
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 20 October 2026.
Read reviews from past customers who have flown Alaska Airlines and Frontier
from Seattle to Ontario. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
There was a delay and my husband needs a wheelchair and we were moved from 1 gate to another.
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.
What airports do I use to fly from Seattle to Ontario?
To fly from Seattle to Ontario, you need to book a flight from Seattle/Tacoma Intl (SEA) to Ontario (ONT). Nonstop flights to Ontario from Seattle/Tacoma Intl take 2h 47m on average. When it comes time to book airfare, you have a few options: there are 10 outbound flights from Seattle/Tacoma Intl to Ontario offered by 2 different airlines.
How popular is this Seattle to Ontario flight route?
Within the past month, 29 users have taken a look at flights from Seattle/Tacoma Intl to Ontario.
How long is the flight from Seattle to Ontario?
For as low as C$ 404, Delta can have you in Ontario from Seattle in 2h 36m. Seattle and Ontario are separated by a distance of 1539 km. All flights are typically direct.
What are the cheapest airlines flying from Seattle to Ontario round-trip?
Cheapflights users have booked flights from Seattle to Ontario round-trip from C$ 251. Another airline that can offer you cheap pricing is Alaska Airlines. Frontier is currently priced 39% below the average price you’ll pay for this route.
What are the most reliable airlines from Seattle to Ontario?
Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Seattle to Ontario on time: Frontier (94%), Volaris (94%), SkyWest Airlines (87%).
What are the cheapest flights from Seattle to Ontario?
Looking for the cheapest flight from Seattle to Ontario? While on average our users pay C$ 231, our data indicates the cheapest price to be C$ 179. The most popular route (Seattle/Tacoma Intl - Ontario), is priced around C$ 235.
Can I find deals for business class flights from Seattle to Ontario?
Yes. Cheapflights offers flight deals from Seattle to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from Seattle to Ontario?
Currently, August is the cheapest month in which you can book a flight from Seattle to Ontario (average of C$ 354). Flying from Seattle to Ontario in February is currently the most expensive (average of C$ 523). 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.
Explore flights to Ontario departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on 20 October 2026.
Discover the top 2 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 20 October 2026.
Find the best flight deals on Cheapflights, where travelers can enjoy low prices and a wide availability of flights to their desired destinations.
How does Cheapflights help users find flights from Seattle to Ontario?
When you search for this flight from Seattle to Ontario, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.
Why should you use Cheapflights to find cheap flight tickets from Seattle to Ontario?
It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Seattle to Ontario.
Can Cheapflights find flights from Seattle to Ontario with no change fees?
Yes! Cheapflights helps users easily find flights from Seattle to Ontario with no change fees.
Can Cheapflights notify me if prices for flights from Seattle to Ontario become cheaper?
Yes, and it’s super simple to set up. Click the bell icon next to the flight deals above and provide a valid email address to enable Price Alerts. That’s it!
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