C$ 313 Find cheap flights from Seattle to London, Ontario

In the last 3 days, the lowest price for a flight from Seattle to London, Ontario was C$ 230 for a one-way ticket and C$ 493 for a round-trip.

We unfortunately don’t have that data for this specific route.

Star Alliance is the only airline alliance operating flights between Seattle and London.

KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Seattle to London.

KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to London from Seattle is likely to change within 7 days, so travelers know whether to wait or book now.

Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to London with an airline and back to Seattle with another airline.

Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to London from Seattle up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.