£128 Cheap Flights from Seattle (SEA) to Toronto (YTO)

Based on fares offered within the last 7 days on Expedia for flights departing within the next year, round-trip journeys between SEA and Toronto (YTO-All Airports) start from £293. Book now to score the best price for your big adventure. Prices and availability are subject to change. Additional terms apply.

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Many airlines offer the option to reschedule your flight without a change fee. All you pay is the difference between the original flight and the new flight. When you're searching for SEA to Toronto (YTO-All Airports) flights, you'll see a "no change fees" filter for you to select.

It's around 3,300 kilometres from SeaTac to Ontario, so expect to be flying for a while. Keep yourself entertained by packing things like a magazine or a thrilling novel.

Check out Air Canada (AC) if you want to fly straight from Sea-Tac Airport to Toronto (YTO-All Airports). This airline offers 30 flights monthly, so you're sure to find one that fits your travel plans.

Late planners can sometimes score a bargain, with some of the cheapest fares from Seattle - Tacoma Intl. Airport (SEA) to Toronto (YTO-All Airports) surfacing a few weeks prior to the departure date. If you'd rather book ahead of time, Expedia compares and updates all the best flight deals continuously — as early as a year in advance in some cases. It does depend on the carrier though, as not all airlines release prices that far in advance.