$394 Cheap Air Canada flights St. Louis (STL) to London (LHR)

You'll find affordable round-trip Air Canada flights from $625 from STL to LHR by sorting your results from "Price (lowest to highest)" on Expedia. Or search for options from $394 for a one-way trip.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.

Look for Air Canada flights from STL to LHR about one month before you want to go. The most affordable time to reserve an international flight is usually 18 to 29 days ahead of your departure date when you can save 17% versus booking four to five months in advance. Regardless of fare class or itinerary, the best day to book international airfare is usually Sunday. Friday can be the most expensive. Travelers booking on a Sunday can save an average of 17% compared to those who book on a Friday.**Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.

Browse Air Canada's earliest flights from STL to LHR by using the "Early Morning" and "Morning" filters. Not only will you arrive sooner, early departures also have a 20% less chance of being canceled.**Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.

Air Canada makes flying from STL to LHR more comfortable with a 4-star airline rating and an excellent in-flight experience. You may even earn points with Air Canada Aeroplan. Don't forget to join Expedia's free One Key™ rewards program to earn OneKeyCash™*, which can be redeemed on future trips.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.