Beginning of main content
Trip Type
Flight 1
Flight 2
Flight 3
Flight 4
Flight 5
Due to coronavirus (COVID-19) travel advisories, some destinations may be unavailable for certain dates. Find out more.

Feel at ease with free flight cancellations within 24 hours of booking

Change your flight without a fee on select flights


Amazing United ONT to SEA Flight Deals

The cheapest flights to Seattle - Tacoma Intl. found within the past 7 days were $160 round trip and $83 one way. Prices and availability subject to change. Additional terms may apply.

SEA From ONT Economy Coach Packages on Similar Airlines


FAQs about United Airlines Flights from ONT to SEA

What terminal is United Airlines at Ontario, CA Airport (ONT-Los Angeles - Ontario Intl.)?

Your ticket usually tells you which terminal your United Airlines flight will be leaving from at Ontario, CA Airport (ONT-Los Angeles - Ontario Intl.). It might also be able to give you the arrival details for Seattle, WA Airport (SEA-Seattle - Tacoma Intl.). If not, you might like to consult your airline.

Are there United Airlines non-stop flights from ONT to SEA?

United Airlines doesn't provide direct flights between Ontario, CA Airport (ONT-Los Angeles - Ontario Intl.) and Seattle, WA Airport (SEA-Seattle - Tacoma Intl.), so be prepared to make a stopover. If you have time to spare between flights, hit the airport shops while you wait for your connection.

How long is an United Airlines flight from ONT to SEA?

Your United Airlines flight from Ontario, CA (ONT-Los Angeles - Ontario Intl.) to Seattle, WA (SEA-Seattle - Tacoma Intl.) will take about 4 hours and 7 minutes. But there are many things you can do to entertain yourself. Asking the passenger beside you about their amazing travel experiences is one of them. If you'd prefer a different sort of in-flight entertainment, you could always listen to some music.

How many direct and indirect flights does United Airlines fly from ONT to SEA?

If you need to lock in a jaunt from ONT to SEA, you can choose from approximately 4 United Airlines flights every day.

Flying Tips & Tricks How do I find my flight number?
  • You'll find a code written in your travel itinerary, which you'll receive when you've finished your booking. Keep your eyes peeled for the IATA airline code (which is one to two letters and a digit) followed by one to four digits — your flight number.
How early can you check bags for a flight?
  • Arriving at the airport early is a great way to ease the stress of traveling. As a rule of thumb, you can check your cabin luggage three hours prior to an international flight and two hours before a domestic one.

*Price based on the lowest price found within past 24 hours and based upon one night stay for two adults over the next thirty days. Prices and availability subject to change. Additional terms may apply.