AirHint found the following cheapest return flights from London (LHR) to Istanbul (IST) in September 2026 (see full year).

Return flights

24 Sep - 06 Oct	Air Serbia
19 Sep - 03 Oct	Air Serbia
27 Sep - 30 Sep	Air Serbia
27 Sep - 29 Sep	Air Serbia
25 Sep - 27 Sep	Air Serbia
05 Sep - 07 Sep	Air Serbia
18 Sep - 20 Sep	Air Serbia
22 Sep - 26 Sep	Air Serbia
15 Sep - 19 Sep	Air Serbia
15 Sep - 23 Sep	Air Serbia
02 Sep - 07 Sep	Air Serbia
23 Sep - 26 Sep	Air Serbia
21 Sep - 01 Oct	Air Serbia
30 Sep - 04 Oct	Air Serbia
28 Sep - 07 Oct	KLM
19 Sep - 03 Oct	British Airways	direct
29 Sep - 07 Oct	British Airways	direct
29 Sep - 03 Oct	British Airways	direct
24 Sep - 06 Oct	British Airways	direct
27 Sep - 03 Oct	British Airways	direct

Also check the deals for one-way flights from London to Istanbul 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 London to Istanbul in September from 151€

Return flights