Flying from Ontario to Seattle, WA can be expensive. Our search helps you compare cheap flights, airfare deals, and flight tickets across airlines and agencies so you can book at the best price.
We scan trusted travel agencies and airline booking systems for the route Ontario - Seattle, WA (ONT - SEA). We do not sell tickets or add fees - you choose where to buy.
Airfares vary by date, time, and airport. Use filters to find the best option by departure/arrival time, number of stops, airline or alliance, and booking channel.
If your dates are flexible, check the low-fare calendar to find the cheapest days. Booking round-trip in one order often reduces fees, and prices usually rise as departure approaches.
We also recommend you to look through the prices for return tickets from Seattle, WA to Ontario.
Airfares found by our users in the past 24 hours
The price for these dates could change. Use search to get the best price.
Average round-trip airfares from Ontario to Seattle, WA by months
| Month | Round-Trip |
|---|---|
| February 2026 | 11.02 - 15.02from £284 |
| March 2026 | 09.03 - 13.03from £93 |
| April 2026 | find now |
| May 2026 | find now |
| June 2026 | 25.06 - 29.06from £161 |
| July 2026 | find now |
| August 2026 | find now |
| September 2026 | find now |
| October 2026 | find now |
| November 2026 | find now |
| December 2026 | find now |
| January 2027 | find now |
Prices shown are based on searches from the last few days. Ticket prices can change and depend on availability at the time of booking.
Airlines are flying from Ontario to Seattle, WA
| Alaska Airlines | Frontier Airlines |
Frequently asked questions about flights from Ontario to Seattle, WA
How long does the flight from Ontario to Seattle, WA take?
Flight duration from Ontario to Seattle, WA varies by route, airline, and number of stops. Direct flights are faster. Use our search to compare options.
Are there direct flights from Ontario to Seattle, WA?
Availability of direct flights from Ontario to Seattle, WA depends on the route and season. Use the "Direct" filter in search to see only direct options.
Which airlines fly from Ontario to Seattle, WA?
Several airlines operate flights from Ontario to Seattle, WA. On this page you see airlines serving this route. Our search compares prices across airlines and agencies.
What is the cheapest month to fly from Ontario to Seattle, WA?
Prices from Ontario to Seattle, WA vary by month and demand. On this page you see average prices by month. Use the low-fare calendar and monthly table to find the cheapest dates.