Compare fares, departure times, stops and baggage details for this route, then open the full search when you are ready to check current availability and complete booking.
ONTSEASat, 03 Oct
Fare checked before payment No hidden charges Transparent cancellation policy 24×7 booking support
Lowest fareUS$218Delta Air Lines
Fastest2h 43mgate to gate
Options found40flights on this route
Find your flightONT → SEA
Available Flights & Fares
Compare fares, timings and baggage. Pick the flight that suits your trip.
Prices in USD
40 flight options
Fares are checked again before payment.
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United Airlines
UA-1387
08:03
2026-10-03
Ontario (ONT)Ontario International
10H :41 M
1 Stop
SFO
· 6h 55m San Francisco (SFO), United States
18:44
2026-10-03
SEATTLE (SEA)Seattle/tacoma International
Non Refundable 9 Seat Left Economy
Check-in: 0 PiecesCabin: 1 Pieces
Type
Non Refundable
Fare Type
Publish
0 Pieces 1 Pieces
$323
Flight DetailsONT to SEA - 10H :41 M
Baggage InfoCheck-in 0 Pieces - Cabin 1 Pieces
Fare RulesNon-refundable fare. Final rules are verified before booking.
United Airlines
UA-1387
08:03
2026-10-03
Ontario (ONT)Ontario International
13H :00 M
1 Stop
SFO
· 9h 07m San Francisco (SFO), United States
21:03
2026-10-03
SEATTLE (SEA)Seattle/tacoma International
Non Refundable 9 Seat Left Economy
Check-in: 0 PiecesCabin: 1 Pieces
Type
Non Refundable
Fare Type
Publish
0 Pieces 1 Pieces
$323
Flight DetailsONT to SEA - 13H :00 M
Baggage InfoCheck-in 0 Pieces - Cabin 1 Pieces
Fare RulesNon-refundable fare. Final rules are verified before booking.
United Airlines
UA-1387
08:03
2026-10-03
Ontario (ONT)Ontario International
15H :24 M
1 Stop
SFO
· 11h 37m San Francisco (SFO), United States
23:27
2026-10-03
SEATTLE (SEA)Seattle/tacoma International
Non Refundable 9 Seat Left Economy
Check-in: 0 PiecesCabin: 1 Pieces
Type
Non Refundable
Fare Type
Publish
0 Pieces 1 Pieces
$323
Flight DetailsONT to SEA - 15H :24 M
Baggage InfoCheck-in 0 Pieces - Cabin 1 Pieces
Fare RulesNon-refundable fare. Final rules are verified before booking.
United Airlines
UA-5330
11:10
2026-10-03
Ontario (ONT)Ontario International
9H :53 M
1 Stop
SFO
· 5h 54m San Francisco (SFO), United States
21:03
2026-10-03
SEATTLE (SEA)Seattle/tacoma International
Non Refundable 9 Seat Left Economy
Check-in: 0 PiecesCabin: 1 Pieces
Type
Non Refundable
Fare Type
Publish
0 Pieces 1 Pieces
$323
Flight DetailsONT to SEA - 9H :53 M
Baggage InfoCheck-in 0 Pieces - Cabin 1 Pieces
Fare RulesNon-refundable fare. Final rules are verified before booking.
No flights match the selected filters. Clear filters or open full search.
Today's Airfare Highlights
Selected flight highlights for 03 Oct 2026.
Lowest fare$218Delta Air Lines06:00
Earliest departure$258United Airlines05:00
Shortest duration$285Alaska Airlines11:13
Night
00:00-05:59
$258United Airlines at 05:00Morning
06:00-11:59
$218Delta Air Lines at 06:00Afternoon
12:00-17:59
$228Delta Air Lines at 13:04Evening
18:00-23:59
$218Delta Air Lines at 18:00
Departure & Arrival Airport Details
Ontario (ONT)
Ontario International
United States
GMT -8
Latitude: 34.055999755859375
Longitude: -117.60099792480469
Seattle (SEA)
Seattle/tacoma International
United States
GMT -8
Latitude: 47.449001
Longitude: -122.308998
Distance: Ontario (ONT), United States to Seattle (SEA), United States - 1,540.37 km
Flights shown for 03 Oct 2026. View all flights opens the complete search result.
Fares and hotel rates usually run higher around these dates. Booking earlier — or shifting a day or two — often costs less.
Busiest periods: Summer travel (15 Jun – 31 Aug), Holiday season (18 Dec – 02 Jan).
12OctColumbus DayMonday · in 30 daysPeak
12OctColumbus DayMonday · in 30 daysPeak
12OctIndigenous Peoples' DayMonday · in 30 daysPeak
11NovVeterans DayWednesday · in 60 days
26NovThanksgiving DayThursday · in 75 days
25DecChristmas DayFriday · in 104 days
Fixed-date national holidays. Festivals that follow the lunar calendar shift each year and are not listed here — check the exact date for your travel year.
Compare your journey
How to travel Ontario to Seattle
Every option we can actually book for you, compared on price and journey time.
Connecting flight₹21,790Longer — includes a stop35 options
Air distance is about 1,540 km. 4 airlines operate this route.
Road distance and coach duration are approximate estimates from the air distance, not a timetable.
Airlines flying from Ontario to Seattle
Compare fares, stops, baggage and refundability across the airlines flying this route.
UN
United Airlines Flights
from $25823 flights
Fares from
$258
Non-stop
None in these results
Departures
23 — compare timings in the list above
AL
Alaska Airlines Flights
from $28510 flights
Fares from
$285
Non-stop
3 in these results
Departures
10 — compare timings in the list above
DE
Delta Air Lines Flights
from $2185 flights
Fares from
$218
Non-stop
2 in these results
Departures
5 — compare timings in the list above
Route Overview & Flight Facts
Fastest flight duration
2h 43m · Alaska Airlines
First departure of the day
05:00 · United Airlines
Last departure of the day
18:00 · Delta Air Lines
Options in this snapshot
40
Direct / non-stop options
5
Airport codes
Ontario–ONT, Seattle–SEA
Fares and timings are indicative — the exact price is confirmed with the airline when you search.
Flight Schedule, Timings & Airfare Insights
Daily Flight Schedule & Travel Duration
Around 40 flights appear in the dated route snapshot, including 5 non-stop options. Departures run through the day — the first flight leaves around 05:00 and the last around 18:00. The fastest flight takes about 2h 43m.
Morning vs Evening Departure Fares
Lowest fare by departure window: Morning from $218, Evening from $218, Afternoon from $228, Night from $258. These observations do not predict the cheapest departure window on other dates.
Cheapest Airfare & Best Time to Book
Search your travel dates to compare current fares — prices update continuously with airline inventory.
One-Way vs Round-Trip Fare Comparison
Compare the complete cost and conditions of both options for your dates. A round-trip can have different fare and change rules from two one-way tickets. One booking may contain multiple airline PNRs; confirm baggage transfer and connection protection for separate tickets.
Online Web Check-In & Boarding Pass
Check the operating airline’s opening time and check-in deadline for each sector. Seat charges and availability depend on your fare. Use the airline reference and the links on Web Check-in.
How to Book Cheap Flights on FlyX
1
Enter your travel details
Choose one-way or round-trip, pick your dates and travellers in the search form above.
2
Compare search results
Sort or filter the Ontario–Seattle results by price, departure time, stops and airline.
3
Open the fare choices
Check baggage allowance and refundability for each fare type before continuing.
4
Review the final price
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5
Pay securely
UPI, cards, net banking and wallets supported; payment and ticket issuance have separate statuses. If issuance is pending, follow the booking status; the confirmed ticket is sent after issuance.
Why Book Your Flight with FlyX?
Compare the available Ontario to Seattle options by total price, stops, baggage and fare conditions. Search your dates for current availability, then review traveller details and the final price before paying.
Payment confirmation and ticket issuance are separate steps. If your booking is awaiting a PNR or ticket, follow its status and contact FlyX support when you need help. Your issued ticket contains the airline reference and itinerary. Change and cancellation charges depend on the purchased fare and any separately disclosed service fee.
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Frequently Asked Questions
Is it worth booking Ontario to Seattle flights in advance?
There is no guaranteed cheapest booking window. Compare your planned dates early, check nearby dates and consider baggage, connection time and change conditions as well as price. Across the dates currently loaded for Ontario to Seattle, Saturday shows the lowest fare at $218. That is an observed snapshot for these dates, not a rule that holds every week.
How far is Ontario from Seattle by air?
The direct air distance between Ontario (ONT) and Seattle (SEA) is about 1,540 km. Actual flight time varies with the routing the airline files and with winds on the day.
Are there non-stop flights from ONT to SEA?
Yes. 5 non-stop flights are showing on Ontario to Seattle for the dates currently loaded. Use the Stops filter to see only those.
Which airlines fly Ontario to Seattle?
United Airlines, Alaska Airlines and Delta Air Lines are showing on this route for the dates currently loaded. Fares, baggage allowance and refund rules differ by airline and by fare type, so compare the fare conditions and not only the headline price.
How long is the flight from Ontario to Seattle?
The quickest non-stop Ontario to Seattle flight currently loaded takes about 2h 43m. Across the non-stop options showing, block time ranges from 2h 43m to 3h. Journeys with a stop take longer, since the total includes the layover.
What is the cheapest Ontario to Seattle flight fare?
The lowest fare showing on Ontario to Seattle for the dates currently loaded is $218. Fares on the same dates run up to $651, depending on airline, timing and fare type. Airline pricing moves continuously, so treat this as a dated observation rather than a fixed price.
What time do Ontario to Seattle flights depart?
For the dates currently loaded the first departure is around 05:00 and the last is around 18:00, local time at Ontario. Use the departure-time filter on the results above to narrow to a morning, afternoon or evening slot.
Why does the price change after clicking Book Now?
Airline seat inventory and fares change continuously. Selecting Book Now runs a live fare verification with the airline so the price you approve is the price you pay - if it has moved, you see the new figure before any payment.
Before you book this route
Check the airport codes ONT–SEA, local departure and arrival dates, and every connecting airport. Connections can have different document and baggage requirements from your final destination.
Where these fares come from
The fares, durations, stops and baggage shown here come from real airline search results for this route. They are examples for the dates on this page, not a full timetable and not a locked price — run a search to see what is available for your own dates.
Last checked .
Check official travel requirements
Confirm passport, visa and transit rules for your nationality and full itinerary with the relevant government and operating airline. IATA travel-document information explains why requirements vary.
Planning more than the flight? Our United States guide covers the visa process for Indian passport holders, best time to go, how long to plan for, and which places are worth the days you have. Long-haul city breaks and national parks.
The ONT to SEA cards above show selected flight options. Airline prices and seat availability can move quickly, so the final fare is rechecked in the booking flow.
Approx route distance: 1,540.37 km.
Before you book
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Lowest Ontario to Seattle airfare today, in 30 days and in 90 days
Cheapest Fare
Fare
Date
Airline
Departure
Lowest Airfare Today
$218
03/10/2026
Delta Air Lines
06:00
Cheapest Airfare Within 30 Days
$214
12/10/2026
Delta Air Lines
06:00
Cheapest Airfare Within 90 Days
$207
11/12/2026
Delta Air Lines
06:00
Book Ontario to Seattle Flight Tickets on FlyX
Planning to fly from Ontario to Seattle? FlyX lets you compare flight rates, airline timings, layovers, and baggage allowances all in one simple list. From quick non-stop routes to flexible connecting options, finding and booking cheap air tickets has never been easier.
Ontario to Seattle Flight Distance, Duration and Time
The aerial distance between Ontario and Seattle is approximately 1,540 KM. The flight duration ranges from 2H :43 M up to 26H :41 M depending on whether you book a non-stop flight or a connecting schedule with layovers.
Ontario to Seattle Flight Schedule and Timing
Around 40 flights operate on this route, providing plenty of choices for your travel window. The earliest morning flight departs from Ontario at 05:00, while the last night flight leaves at 18:00. Flights depart from Ontario International and land at Seattle/tacoma International.
Flight Route Details & Analysis
Flight Details
Information
Route
Ontario to Seattle
Aerial Distance
1,540 KM
Flight Duration
2H :43 M - 26H :41 M
Airport Codes
Ontario - ONT, Seattle - SEA
Total Flights Available
40 flights (5 direct)
First Flight Departure
Departs at 05:00
Last Flight Departure
Departs at 18:00
Early Morning Flights (12 AM - 8 AM)
11 direct/indirect flights
Morning Flights (8 AM - 12 PM)
13 direct/indirect flights
Afternoon Flights (12 PM - 4 PM)
9 direct/indirect flights
Evening Flights (4 PM - 8 PM)
7 direct/indirect flights
Night Flights (8 PM - 12 AM)
0 direct/indirect flights
Airport Information & Terminals
ONT: Ontario airport. Ontario airport transfer should be matched to the exact hotel, suburb or meeting area. Rail can work well for light luggage, but late arrivals, winter weather and family baggage often make a direct cab or booked transfer easier.
SEA: Seattle-Tacoma International Airport. Sea-Tac connects to downtown by light rail, while cabs are useful for Bellevue, Redmond or late-night arrivals. Rain and freeway traffic should be part of the plan.
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Ontario International
