Cheap flights from Ontario to Seattle from $134

In general, February is the cheapest month to fly from Region of Ontario to Seattle. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $260. If you don’t want to visit Seattle in February, then you should wait until November to fly from Region of Ontario, when ticket prices are also cheap, with an average price of $307.

On average, the least expensive day to fly to Seattle from Region of Ontario is on a Thursday. momondo users have found tickets for Thursday departures for as low as $400. However, this price may fluctuate depending on the airline, the season, and holidays. On the other hand, Sunday is the most expensive day to depart from Region of Ontario because it is more convenient for both business and leisure travelers. As a result, prices tend to be around $645.

Flying to Seattle from Region of Ontario in the evening is the least expensive time of day to depart. momondo users have found prices as low as $397 when looking at flights departing in the evening. Flights to Seattle are more costly in the morning, with an average ticket price of $526. Departure times in the morning fall within the peak daily travel times, which is why tickets can be more expensive.

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

You are more likely to see cheaper flights to Seattle from Region of Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to Seattle for around $340 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Seattle from Region of Ontario for as low as $298 on momondo.

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

Air Canada, Alaska Airlines, and WestJet are the most popular carriers operating from Ontario to Seattle/Tacoma Intl

Air Canada, Alaska Airlines and WestJet are the top three most popular airlines that fly to Seattle from Region of Ontario according to our data. Air Canada is the first choice among our users, with 38% of people opting to fly with this airline when traveling to Seattle. Keep in mind that there are 6 different airlines that fly to Seattle on a routine basis, so you have a few additional options to choose from.

As of February 2026, 5 flights take off from Region of Ontario and land in Seattle each day. The most common flight departure time for this route is 4:00PM, with 51% of daily flights taking off in the afternoon.

The number of flights available between Region of Ontario and Seattle is 41 per week as of February 2026. The most frequent departure day is Mon, with 15% of weekly flights leaving on this day.