AirHint found the following cheapest return flights from St. Louis (STL) to London (LHR) in August 2025 (see full year).

Return flights

17 Aug - 26 Aug	Delta
13 Aug - 21 Aug	British Airways
12 Aug - 19 Aug	British Airways
12 Aug - 25 Aug	KLM
08 Aug - 15 Aug	Delta
17 Aug - 30 Aug	Delta
21 Aug - 28 Aug	British Airways
15 Aug - 20 Aug	British Airways
25 Aug - 01 Sep	British Airways
22 Aug - 25 Aug	Air Canada
23 Aug - 30 Aug	British Airways
31 Aug - 07 Sep	British Airways
27 Aug - 07 Sep	Air Canada
27 Aug - 05 Sep	British Airways
27 Aug - 04 Sep	British Airways
27 Aug - 03 Sep	British Airways
28 Aug - 01 Sep	Iberia

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

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 August from $520

Return flights