$109 Cheap Delta flights Ontario (ONT) to Seattle (SEA)

View $109 flight on Sat, Aug 23, 2025Opens in a new window

$109 Cheap Delta flights Ontario (ONT) to Seattle (SEA)

Prices were available within the past 7 days and start at $109 for one-way flights and $177 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Sat, Aug 23 - Wed, Aug 27
ONT
Ontario
SEA
Seattle
$177 Roundtrip, just found
$177
Roundtrip
just found
Select Delta flight, departing Sat, Aug 23 from Ontario to Seattle, returning Wed, Aug 27, priced at $177 just found
Delta
Sat, Aug 23 - Wed, Aug 27
ONT
Ontario
SEA
Seattle
$200 Roundtrip, just found
$200
Roundtrip
just found
Select Delta flight, departing Sat, Aug 23 from Ontario to Seattle, returning Wed, Aug 27, priced at $200 just found
Flights from Ontario (ONT) to Seattle (SEA)
Origin airport
Los Angeles - Ontario Intl.
Destination airport
Seattle - Tacoma Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Popular airline
Alaska Airlines
Distance
956 mi
Average flight time
2 hours 44 mins

Frequently asked questions

How much is a Delta Air Lines flight from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA)?
You can discover budget-friendly return Delta Air Lines flights from $177 from ONT to SEA by organizing your results from "Price (lowest to highest)" on Expedia. Or search for deals from $109 for a one-way journey.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from ONT to SEA with Delta Air Lines?
January is one of the cheapest months to fly to Seattle with Delta Air Lines. You could also find great prices on one-way and return fares in February.
What is the cheapest time to book flights from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA) with Delta Air Lines?
Start searching one to three months ahead of your travel date to find cheap fares on Delta Air Lines flights from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA). You can save 25% by booking your domestic flight 34 to 86 days in advance versus last-minute reservations made 6 to 12 days out. You could also cut costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Get your timing spot on, and you can enjoy significant savings on domestic trips.*Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does Delta Air Lines fly nonstop from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA)?
Book a seat on one of Delta Air Lines's 14 direct weekly flights from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA). To see your choices, enter your dates, origin and destination and hit search. Then use the "Nonstop" and "Airline" filters.
How long does it take to fly from ONT to SEA with Delta Air Lines?
Depart Los Angeles - Ontario Intl. Airport (ONT) for Seattle - Tacoma Intl. Airport (SEA) on a direct Delta Air Lines flight, and you'll be airborne for approximately 2h 55m.
Which day of the week has the most Delta Air Lines flights from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA)?
If you're looking for flexibility, Thursday offers the most choice for Delta Air Lines flights from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA). You can select from 2 different departures.
What is the earliest Delta Air Lines flight from ONT to SEA?
The first flight from ONT to SEA with Delta Air Lines departs at 6:00AM UTC-8. You'll land at 8:55AM UTC-8. The final Delta Air Lines flight of the day takes off at 4:05PM UTC-8 and arrives at 7:00PM UTC-8. With approximately 20% fewer cancellations for morning departures, jetting out early is often the smartest option.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does Delta Air Lines fly into in Seattle?
Delta Air Lines flights from Los Angeles - Ontario Intl. Airport (ONT) to Seattle come in to land at Seattle - Tacoma Intl. Airport (SEA). This is the main entry point to this destination.
Why fly with Delta Air Lines from ONT to SEA?
With an excellent in-flight experience and a rewarding loyalty program, Delta Air Lines is a favorite for many passengers heading from ONT to SEA. Plus, if you're a Delta SkyMiles and One Key™ member booking with Expedia, you could earn OneKeyCash™* on eligible flights on top of your airline miles, which can be put toward future travel.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
What type of plane does Delta Air Lines fly from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA)?
Chances are you'll travel on an Embraer 175 for your Delta Air Lines flight from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA). However, you could end up on an alternative aircraft if operational demands require it.
Can I change or cancel my Delta Air Lines flight from Los Angeles - Ontario Intl. Airport (ONT) to Seattle - Tacoma Intl. Airport (SEA)?
You can usually reschedule or cancel your flight, although there may be a charge if you booked over 24 hours ago. Want to keep your options open? Make use of Expedia's "No cancel fee" or "Changes included" filter to find flights that won't penalize you if you have to adjust your plans. To modify your booking, visit "Trips," select your flight and click on "Manage Booking" for further information.

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*Available to One Key members.