AirHint found the following cheapest return flights from Dallas (DAL) to London (LHR) in September 2025 (see full year).

Return flights

23 Sep - 30 Sep	Air France
10 Sep - 30 Sep	Air France
08 Sep - 30 Sep	Air France
01 Sep - 16 Sep	Delta
27 Sep - 07 Oct	Delta
04 Sep - 17 Sep	Delta
05 Sep - 16 Sep	Air France
08 Sep - 20 Sep	Air France
22 Sep - 29 Sep	Delta
02 Sep - 08 Sep	Air France
03 Sep - 08 Sep	KLM
25 Sep - 03 Oct	Air France
29 Sep - 04 Oct	Scandinavian Airlines
25 Sep - 11 Oct	Delta
13 Sep - 04 Oct	KLM
20 Sep - 11 Oct	Air France
19 Sep - 11 Oct	Virgin Atlantic
30 Sep - 04 Oct	Scandinavian Airlines
22 Sep - 18 Oct	Air France
17 Sep - 11 Oct	KLM

Also check the deals for one-way flights from Dallas to London in September.

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 Dallas to London in September from $641

Return flights