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

Return flights

05 May - 13 May	Delta
06 May - 12 May	Delta
01 May - 05 May	Air Canada
08 May - 12 May	Delta
01 May - 17 May	Air Canada
07 May - 11 May	Air Canada
06 May - 03 Jun	Air Canada
01 May - 04 May	Air Canada
01 May - 09 May	Delta
08 May - 16 May	Delta
15 May - 19 May	Delta
18 May - 03 Jun	Delta
01 May - 01 Jun	Air Canada
20 May - 06 Jun	Air Canada
16 May - 20 Jun	KLM
31 May - 06 Jun	Air Canada
06 May - 03 Jun	Finnair	direct

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 $656

Return flights