How popular is this Ontario to Seattle flight route?

The Ontario to Seattle/Tacoma Intl flight path was viewed by 255 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

How long is the flight from Ontario to Seattle?

There are many flights that can get you from Ontario to Seattle in 2h 43m. Fly via Southwest or Hawaiian Airlines to get the fastest option. There are 956 mi between Ontario and Seattle. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

What are the cheapest airlines flying from Ontario to Seattle round-trip?

Cheapflights users have booked flights from Ontario to Seattle round-trip from $75. Other airlines that can offer you cheap pricing are Hawaiian Airlines, from $98, and Delta, from $117. You may be able to fly from Ontario to Seattle for 62% less than the average price by searching for these airlines.

How far ahead should I book a flight from Ontario to Seattle?

To ensure you get the cheapest price possible for a flight from Ontario to Seattle, you should look to book at least 90 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

What is the cheapest month to book a flight from Ontario to Seattle?

Currently, January is the cheapest month in which you can book a flight from Ontario to Seattle (average of $238). Flying from Ontario to Seattle in June is currently the most expensive (average of $388). 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 day to fly from Ontario to Seattle?

Travelers seeking maximum savings on their Ontario to Seattle flight should consider departing on Friday mornings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Ontario to Seattle

The most flights from ONT to SEA are scheduled on a Thursday (21 on average). You will have fewer flight options on Monday, which is when the least amount of flights are scheduled (7 on average).

In terms of precipitation, rainfall in Seattle ranges from 0.7 - 6.6 inches per month. November is typically the wettest month, when rainfall can reach 6.6 in. July is typically the driest time to visit Seattle when rainfall is around 0.7 in.

If weather is an important factor for your trip to Seattle, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 66.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 41.0 F).

What are the cheapest flights from Ontario to Seattle?

While on average a flight from Ontario to Seattle is generally $389, our data shows the cheapest flight currently is $75. When looking at the most popular route, (Ontario - Seattle/Tacoma Intl), you can expect to pay $53 for that flight.

What are the most reliable airlines from Ontario to Seattle?

Consider Scandinavian Airlines (96%), Japan Airlines (95%) or Frontier (95%) when booking your flight. These represent the most reliable airlines when flying from Ontario to Seattle.

What are the most popular airlines that fly from Ontario to Seattle?

Alaska Airlines, Delta and Frontier are the most popular airlines when flying from Ontario to Seattle.

What is the cheapest day to fly round-trip from Ontario to Seattle?

Flights from Ontario to Seattle are found to be more expensive on Monday. This shouldn't discourage you from searching as you can still find great deals by being flexible with your options. Use our search form to find deals on tickets to Seattle.

How far in advance should I book a flight from Ontario to Seattle?

Users have found that booking a flight from Ontario to Seattle at least 59 days early can save you up to 79% on average compared to booking a flight this week. If booking 59 days before your flight isn’t an option for you, users have found flights from Ontario to Seattle for as little as $265 when booking for a departure date within the next two weeks. You can also check prices now. Some users have found airline tickets as low as $343 for flights departing within the next 3 days.

What is the cheapest month to fly from Ontario to Seattle?

January can be a great time to fly to Seattle from Ontario with a flight ticket averaging about $211. Cheapflights users have found deals in the month of January for as cheap as $38. The most expensive prices can be found in the month of July.

What is the cheapest time of day to fly from ONT to SEA?

It’s typically best to fly out from Ontario to Seattle in the morning. Doing so could potentially save you 22% on the flight price compared to flying at noon, which is usually more expensive.

What airports do I use to fly from Ontario to Seattle?

If you wish to fly to Seattle from Ontario, then you need to book flights from Ontario to Seattle/Tacoma Intl. There are 11 flights from Ontario (ONT) to Seattle/Tacoma Intl (SEA) per day to choose from. Flights to Seattle from Ontario are available from 5 different airlines, which means you should have some options if you want to compare airfare deals. 2h 40m is how long a nonstop flight from Ontario to Seattle/Tacoma Intl typically takes.

Can I find deals for flights from Ontario to Seattle that include hotel bookings?

Yes. In addition to deals on Ontario to Seattle flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Ontario to Seattle?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Seattle.

Can I find deals for business class flights from Ontario to Seattle?

Yes. Cheapflights offers flight deals from Ontario to Seattle by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$90+ Cheap Flights from Ontario to Seattle

Round-trip from	$121 (Kiwi.com)
One-way from	$90 (Kiwi.com)
Popular in	July
Cheapest in	January
Average price	$186
Good round-trip deal	$177 or less
Good one-way deal	$120 or less

Frontier offers extra comfort seats with 32” separation for a fee, ideal for taller passengers.

Frontier's Board First option allows early boarding for carry-on bag purchasers and elite members.

Airline	Cheapest	Average	Flexibility	On-time
Frontier	Cheapest$75	Average$168	FlexibilityNo cancel fee	On-time62%
Hawaiian Airlines	Cheapest$98	Average$249	FlexibilityNo cancel fee	On-time85%
Delta	Cheapest$117	Average$255	FlexibilityNo cancel fee	On-timeN/A
Alaska Airlines	Cheapest$148	Average$264	FlexibilityNo cancel fee	On-time75%
Southwest	Cheapest$150	Average$270	FlexibilityNo cancel fee	On-time63%

$90+ Cheap flights from Ontario to Seattle (ONT - SEA)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/12. Fares are subject to change and may not be available on all flights or dates of travel.

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Cheapflights Tip: The best prices from Ontario to Seattle/Tacoma Intl are usually found in January or October, booked 90 days in advance, depart on a Friday or Thursday and return on a Tuesday

Cheap flight deals from Ontario to Seattle

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Find flight deals from Ontario to Seattle

Cheapest flights from Ontario to SeattleExplore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 11, 2025.

Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 11, 2025.

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The best insider tips for Ontario to Seattle flights

Cheapflights partnered with top experts to bring you the best recommendations for your Ontario to Seattle trip

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Best time to book a flight from Ontario to Seattle

Have a flexible travel schedule? Discover the best time to fly to Seattle from Ontario with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Ontario to Seattle

How far ahead should I book a flight from Ontario to Seattle?

What is the cheapest month to book a flight from Ontario to Seattle?

What is the cheapest time of day to fly from ONT to SEA?

What is the cheapest day to fly from Ontario to Seattle?

Weekly flight availability from Ontario to Seattle

Reviews of airlines servicing Seattle

See what other customers who have flown with Alaska Airlines, Southwest, and Delta from Ontario to Seattle have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

Find useful and relevant information for your journey from Ontario to Seattle. 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 Ontario to Seattle?

How popular is this Ontario to Seattle flight route?

How long is the flight from Ontario to Seattle?

What are the cheapest airlines flying from Ontario to Seattle round-trip?

What are the most reliable airlines from Ontario to Seattle?

What are the cheapest flights from Ontario to Seattle?

Can I find deals for flights from Ontario to Seattle that include hotel bookings?

How can I find direct flights from Ontario to Seattle?

Can I find deals for business class flights from Ontario to Seattle?

What is the cheapest month to book a flight from Ontario to Seattle?

Traveling to a place near Seattle?

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Cheapest flights from Ontario to Seattle
Explore the most affordable flight options available from Ontario to Seattle. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 11, 2025.