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

Return flights

01 May - 08 May	Air Canada
13 May - 06 Jun	Air Canada
19 May - 05 Jun	Air Canada
15 May - 17 May	United
19 May - 05 Jun	British Airways	direct
04 May - 07 May	Air Canada
05 May - 08 May	Air Canada
12 May - 15 May	Air Canada
17 May - 31 May	Air Canada
05 May - 08 May	British Airways	direct
12 May - 15 May	British Airways	direct
14 May - 17 May	Finnair
17 May - 06 Jun	Air Canada
17 May - 31 May	British Airways	direct
31 May - 30 Jun	United

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

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 May from 589€

Return flights