$99 Cheap Delta flights Seattle (SEA) to Ontario (ONT)

View $99 flight on Tue, Aug 26, 2025Opens in a new window

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$99 Cheap Delta flights Seattle (SEA) to Ontario (ONT)

Prices were available within the past 7 days and start at $99 for one-way flights and $157 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Wed, Aug 27 - Tue, Sep 2
SEA
Seattle
ONT
Ontario
$157 Roundtrip, just found
$157
Roundtrip
just found
Select Delta flight, departing Wed, Aug 27 from Seattle to Ontario, returning Tue, Sep 2, priced at $157 just found
Flights from Seattle (SEA) to Ontario (ONT)
Origin airport
Seattle - Tacoma Intl.
Destination airport
Los Angeles - Ontario Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Hawaiian Airlines, Southwest Airlines, United
Popular airline
Alaska Airlines
Distance
956 mi
Average flight time
2 hours 47 mins

Frequently asked questions

How much is a Delta Air Lines flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Finding cheap one-way Delta Air Lines flights from SEA to ONT from $99 on Expedia couldn't be easier — just filter by "Price (lowest to highest)." Alternatively, check out our budget-friendly return fares from $157 for your next adventure.**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 SEA to ONT with Delta Air Lines?
January is one of the most affordable months to get away to Ontario with Delta Air Lines. You could also find fantastic deals on one-way and return fares in April.
What is the cheapest time to book flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT) with Delta Air Lines?
For cheap Delta Air Lines fares from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT), start searching one to three months before your intended departure. Reserving domestic flights 34 to 86 days in advance could save you 25% compared to booking just 6 to 12 days ahead. The day you book can also influence the cost. Sunday is usually the cheapest, while Monday is often the most expensive for domestic flights. You can save 6% on average by booking your trip on a Sunday.**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 Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Delta Air Lines has direct flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT), with 14 departures each week. Simply apply the "Nonstop" and "Airline" filters while searching on Expedia to find all direct Delta Air Lines flights to ONT.
How long does it take to fly from SEA to ONT with Delta Air Lines?
Leave Seattle - Tacoma Intl. Airport (SEA) for Los Angeles - Ontario Intl. Airport (ONT) on a direct Delta Air Lines flight, and you'll be in the air for around 2h 46m.
Which day of the week has the most Delta Air Lines flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Thursday has the most Delta Air Lines flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT). With 2 daily departures, this is the best day of the week to book something that will work for your schedule.
What is the earliest Delta Air Lines flight from SEA to ONT?
Leaving SEA at 12:40PM UTC-8, the earliest Delta Air Lines flight to ONT arrives at 3:25PM UTC-8. Flying early means you'll be less likely to encounter delays or cancellations.* Prefer a later start? The last Delta Air Lines flight from SEA to ONT departs at 7:45PM UTC-8 and touches down at 10:32PM UTC-8.*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 Ontario?
Los Angeles - Ontario Intl. Airport (ONT) is the main Ontario gateway for Delta Air Lines flights from Seattle - Tacoma Intl. Airport (SEA). Los Angeles Intl. Airport (LAX) and John Wayne Airport (SNA) are other possibilities. When planning your vacation with Expedia, select the "All Airports" option for your destination to see all available choices.
Why fly with Delta Air Lines from SEA to ONT?
With an excellent in-flight experience and a rewarding loyalty program, Delta Air Lines is a favorite for many passengers heading from SEA to ONT. 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 you can put toward future getaways.*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 Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Delta Air Lines typically uses Embraer 175 planes for flights from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT). Bear in mind that aircraft type can differ depending on operational needs, so the plane you'll be on might be different on your day of travel.
Can I change or cancel my Delta Air Lines flight from Seattle - Tacoma Intl. Airport (SEA) to Los Angeles - Ontario Intl. Airport (ONT)?
Changes are typically free within 24 hours of making your booking, but your airline may add a charge after that. For more information about modifying your reservation, check out your "Trips," select your flight and click on "Manage Booking." If you want the freedom to change your itinerary without extra charges, tick the "No cancel fee" or "Changes included" filter when planning your trip.
*Available to One Key members.