AirHint found the following cheapest return flights from St. Louis (STL) to London (LHR) in March 2026 (see full year).

Return flights

03 Mar - 10 Mar	British Airways
18 Mar - 25 Mar	British Airways
25 Mar - 18 Apr	Air Canada
22 Mar - 11 Apr	Air Canada
07 Mar - 14 Mar	Air Canada
15 Mar - 04 Apr	Air Canada
23 Mar - 30 Mar	British Airways
07 Mar - 28 Mar	Air Canada
08 Mar - 15 Mar	British Airways
28 Mar - 04 Apr	British Airways
22 Mar - 27 Mar	Air Canada
13 Mar - 20 Mar	British Airways

Also check the deals for one-way flights from St. Louis to London in March.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from St. Louis to London in March from $661

Return flights