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

Return flights

13 May - 20 May	Air Canada
01 May - 08 May	Air Canada
08 May - 15 May	Air Canada
03 May - 10 May	Air Canada
01 May - 05 May	Air Canada
12 May - 26 May	Delta
08 May - 15 May	British Airways	direct
01 May - 04 May	Air Canada
19 May - 26 May	Delta
15 May - 17 May	United
12 May - 29 Jun	Frontier Airlines
23 May - 07 Jun	Air Canada
27 May - 23 Jun	WestJet
29 May - 25 Jun	Alaska Airlines

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.

Book a cheap hotel in London

Cheap car rent in London

Cheapest return flights from St. Louis to London in May from 551€

Return flights