Cheap flights from Seattle to Ontario from $112

The month of January is, on average, the cheapest month to fly to Region of Ontario from Seattle, with most prices found around $274. If you aren’t able to travel during the month of January, then book flights to Region of Ontario from Seattle during November instead. Flights to Region of Ontario in November, while not as cheap as those in January, still average around $310.

According to our data, Tuesday is the cheapest day to fly to Region of Ontario from Seattle. The lowest ticket price found for a Tuesday departure recently was $536. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. Flights from Seattle to Region of Ontario on a Sunday will generally be more expensive and average around $764. Keep in mind that these prices on both days could fluctuate depending on the season and the demand.

Fly from Seattle/Tacoma Intl to Toronto Pearson Intl for the best Seattle/Tacoma Intl - Ontario flight prices

You are more likely to see cheaper flights to Region of Ontario from Seattle when booking weeks ahead of your departure date. In general, you can expect to find flights to Region of Ontario for around $406 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Region of Ontario from Seattle for as low as $318 on momondo.

There are 4 cabin classes available to choose from on Seattle to Region of Ontario flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

You could potentially save up to 38% on your flight if you consider stops on a Seattle to Region of Ontario flight.

WestJet, United Airlines, and Delta are the most popular carriers operating from Seattle/Tacoma Intl to Ontario

Alaska Airlines, Air Canada and WestJet are the top three most popular airlines that fly to Region of Ontario from Seattle according to our data. Alaska Airlines is the first choice among our users, with 47% of people opting to fly with this airline when traveling to Region of Ontario. Keep in mind that there are 5 different airlines that fly to Region of Ontario on a routine basis, so you have a few additional options to choose from.

The number of flights available between Seattle and Region of Ontario is 3 per day as of September 2026. The most frequent departure time is 8:00AM, with 100% of daily flights leaving at noon.

25 flights are operational weekly from Seattle to Region of Ontario as of September 2026. The most popular departure day for this route is Mon, with 20% of flights per week taking off on this day.